Recent Advances in Structural Engineering

This review article focuses on the design and analysis of multi-storied buildings with floating columns in various seismic zones of India. The article presents a detailed analysis of the behavior of floating column structures under seismic loads and evaluates their effectiveness in mitigating effects of earthquakes. The review highlights various design parameters such as column layout, structural configuration, and seismic provisions that play a significant role in ensuring the safety of such structures during seismic events. The study reviews various research works on the design and analysis of floating column structures carried out by researchers in India and abroad. The review also summarizes the seismic code provisions of India and other countries related to the design of floating column structures. The review concludes that floating column structures are an effective way to mitigate the impact of earthquakes on multi-storied buildings. However, the effectiveness of such structures depends on various design parameters and the seismic zone in which they are located. The study recommends further research to develop optimal design strategies for floating column structures in different seismic zones of India.

Fiber reinforced polymer (FRP) has gained significant attention as a material for pile reinforcement due to its superior mechanical properties such as high strength, durability, and corrosion resistance. In this study, carbon fiber reinforcement polymer (CFRP) and basalt fiber reinforcement polymer (BFRP) are used for FRP piles. The major goal of this study is to assess the mechanical strength of piles with or without FRP. To achieve this goal, numerical modeling of FRP pile has been performed. The numerical modeling of FRP piles has been carried out in ABAQUS software in which a four-point bending test has been performed by using a concrete damage plasticity model. To obtain the behavior of FRP materials, experimental work has been carried out in this study which includes the compressive strength, tensile strength, and flexural strength. The result shows that the flexural strengths of conventional beam, CFRP beam, and BFRP beam are 4.2, 7, and 6.6 MPa. Also, a validation study has been carried out between experimental work and numerical modeling in which the error difference of flexural strength between experimental work and numerical modeling is found to be 6.3%, 5.1%, and 6%, respectively. The performance of piles has been evaluated in terms of strengths, failure analysis, stress, and strain profile. The significance of this study is to minimize the maintenance cost of piles during its service life and to reduce the risk of damage or failure of piles under marine conditions.

The present study conducted an experimental investigation on the behaviour of square high-performance concrete (HPC) slender columns. A total of 81 square high-performance slender (SHPS) columns were constructed and subjected to uniaxial and biaxial loading, with the aim of examining their performance. The key parameters investigated in the tests were the grade of HPC (ranging from M60 to M80), reinforcement ratios (ranging from 2.01 to 4.52%), and an eccentricity along the 20% from the major axis. The test results show that these parameters significantly influenced the strength and behaviour of square high-performance slender columns. Notably, the steel reinforcement was found to be a crucial factor affecting the bearing capacity of the column specimens, as demonstrated in the experiments. Furthermore, the load-carrying capacity of the specimens exhibited a substantial increase with higher grades of concrete. To accurately determine the material behaviour of square high-performance slender columns, constitutive models were developed and validated against the experimental data using the non-linear finite element software. Comparing the experimental failure loads with the predicted failure loads based on the FEM method yielded favourable agreement. From the experimental results, it was that as the load increased, the deflection decreased for both uniaxially and biaxially loaded columns, highlighting the novelty of this finding. Additionally, the columns subjected to biaxial loading displayed greater sensitivity compared to their uniaxial loading.

The utilization of hybrid concrete has experienced rapid growth in today’s context, as it offers sustainable construction solutions. In light of this development, the present research focuses on investigating the viability of incorporating waste quarry dust obtained from Kotre, Gandaki Province, in Nepal as a partial replacement for fine aggregates in traditional concrete. To achieve this, a simulation based on Finite Element Method (FEM) is employed to compare the compressive and flexural strength of concrete specimens determined through laboratory testing. The study evaluates the accuracy and reliability of this simulation approach in predicting the hardened properties of concrete. Initially, the mechanical properties of the concrete specimens are examined under laboratory conditions to establish a baseline. Subsequently, computational modeling is utilized to predict the strengths of identical specimens. By contrasting the simulation’s outcomes with the actual data from the lab, the accuracy of the models in forecasting specimen strengths is assessed. The outcomes of this research carry significant implications for the adoption of hybrid concrete in sustainable structures and underscore the importance of numerical simulations in designing and analyzing concrete constructions.

Skew bridge footings are an important aspect of bridge construction, especially when dealing with bridges that cross over rivers, valleys, or other obstructions at an angle. The importance of skew bridge footings lies in their ability to provide stability and ensure the structural integrity of the bridge. When a bridge is constructed at an angle, the distribution of weight and load is different than that of a straight bridge. Skew pier bridges present unique challenges in modeling their fundamental frequency dynamics due to their asymmetric geometry and varying load distribution. Skew pier bridges have an asymmetric geometry that makes it difficult to model the fundamental frequency dynamics using traditional methods. Another factor that can affect the fundamental frequency dynamics of a skew pier bridge is the presence of irregularities in the structure, such as cracks, joints, or other defects. Factors such as irregularities in the structure, changes in the cross-section, or other local effects can also significantly affect the fundamental frequency of the deck and may require more advanced analysis techniques to accurately predict. Herein, a brief review is presented on the empirical and semi-empirical formulas for determining the fundamental frequency of footings and deck of skew bridges. Then, finite element analysis has been employed to examine how the skewness affects the bridge with T-beam deck slab’s fundamental frequency. A validation study has been carried out and a good comparison was observed. In order to determine the skewness effect, numerical studies have been conducted on T-bridge with support skewness ranging from 0° to 30°. Results show that the change in the skewness of supports results in the significant change of the fundamental vibration frequency.

In the current study, the manual approach and SAP2000 software are used for gravity and lateral loads analysis and also the design characteristic of raised water tank constructions is considered as the main focus of interest. A typical Intze water tank is utilized for the study. Using a combination of plate and line elements, the structure is modeled using SAP2000 software. The gravity loading is composed of the structure's own weight, vertical and horizontal water pressure, and both. Seismic forces contributing are considered by changing the value of Seismic Response Reduction Factor (R). IS: 1893-2016 and IS: 875-1987 (Part III). Combinations incorporating gravity and lateral loading are examined for the structure. In general, all designs of water tanks are subjected to Dead Load, Live Load and Wind Load/Earthquake load as per IS Code of practice. Additionally, pushover analysis is done. The structure is then created utilizing manual and SAP2000 procedures for the internal forces. The results show that SAP2000 is useful and efficient for the analysis and design of water tanks. The pushover curve shows how ductile the structure is. Both manual methods and SAP2000's design output are in perfect agreement.

The Bureau of Indian Standards (BIS) has recently made significant revisions to the IS:3370—Concrete Structures for Retaining Aqueous Liquids—Code of Practice. Along with the changes in construction materials and procedure, major revisions have been made in the code of practice. Load calculations, permissible stresses, minimum reinforcement, and the overall design process have been revised. This has led to better designing of water tanks. To demonstrate the impact of the revised code, an Elevated Water Reservoir has been designed using both IS:3370-2009 and IS:3370-2021. The results have been compared to understand the effect of revision of code on the designing process. The revised code presents an opportunity for enhanced structural design practices, ensuring simpler solutions for designing of elevated storage reservoirs. The comparison presented in this paper will serve as a valuable reference for professionals involved in the design and construction of water tanks, offering a comprehensive understanding of the effects brought about by the revisions in IS:3370.

All around the world, free-standing stone walls are extremely common. They are widely used as private land, household gardens, and industrial and commercial premises barriers. Free-standing walls are built between pilasters, which are rectangular projectile columns made of masonry blocks that offer extra support to the filling wall and base. The pilaster is built at predetermined intervals throughout the wall’s length and cantilevered up from the foundation. Masonry units that stretch horizontally between pilasters are known as fillers. Free-standing walls are generally subject to lateral loads such as wind loads, ground pressure, and so on. This research studies the prevalence of several forms of cracks in free-standing masonry walls, which are caused by vegetation growth, differential settling, and other factors that cause the failure of the compound wall. Every filler wall between the pilasters is measured and surveyed to determine its deflection and height from the foundation. More deflection is observed along the length of the free-standing wall in the mid-region between the pilasters, and we may compare the deflection by imagining the free-standing masonry wall with the pilaster using survey data. According to the findings of this study, the brick wall is deflected due to vegetation growth and foundation sinking, and weathering action leads the wall to expand and compress, creating fractures.

Bridge, a Civil Engineering structure, used since ancient times for crossing any obstruction beneath it. From the past decades, bridges are constructed using different kinds of materials starting from wood to structural steel, which is now has become a large field of study at this period of time. Among different types of skywalk bridges fall under the special category, since it has to be specially designed both in architectural and structural point of view and are commonly used in hill stations and rocky areas as an attraction for visitors. Skywalks have the best features of a cantilever and allow to view both sides. In this present work, an innovative steel skywalk bridge is planned to construct by choosing a suitable viewpoint on Chamundi Hills, Mysuru based on the topography, slope, and its stability. Preliminary reconnaissance survey has been carried out. The objective of the present work is to find the framing system to support the cantilever skywalk at one location and also to find the optimum span and dimension of structural members. Skywalk for various cantilever projection is modeled in ETABS, and checked for criticality such as increase in deflection and moments’ overall stability. For the three cases, key results such as cantilever deflection, bending moments in beams and axial forces in critical columns and bracings and finally, sway due to earthquake are presented. The case 3 is found to be efficient framing system, since cantilever moment is reduced to 82 kN m, and also side sway.

The conduction of laboratory experiments on concrete is very costlier and time-consuming. Hence numerical simulation technique like Finite Element Analysis (FEA) which is used in industries and research centers to analyze the behavior of various structural components has made it possible to model and simulate the complex behavior of reinforced concrete elements. This paper presents a nonlinear Finite Element Analysis (FEA) carried out to simulate the load–deflection behavior of Control Concrete (CC) beam and Steel Fiber-Reinforced Concrete (SFRC) beams under monotonic loading in flexure. The objective of this study is to investigate and validate the load–deflection characteristics of M20 grade CC and SFRC beams with hooked-end steel fibers of aspect ratio 50 (a/d = 50) with steel fibre dosages of 1.0, 1.25, 1.5, and 1.75% of total volume of concrete. FE studies were carried out on both CC beam and SFRC beam which were analyzed using FEM software package ANSYS Mechanical APDL 2022 R2. From the FE analyses, load–deflection responses and crack patterns were obtained and validated with the referred experimental results. The load–deflection responses obtained from the FE studies showed good correlations with the experimental plots. Hence, modeling of SFRC beams can be adoptable in ANSYS and the proposed FE models were found to be reliable for analyzing the flexural behavior of SFRC member subjected to monotonic loading.

This study summarizes the concern of progressive collapse in buildings, which refers to the failure of a building’s structural components when a critical element is lost. The paper highlights a historical overview of this phenomenon and examines the causes and current state of research in the field. This review also discusses various design strategies for preventing progressive collapse, including redundancy, alternate load paths, and ductility, and emphasizes the crucial role of regulations in ensuring building safety. This study suggests areas for further research and recommendations for improving regulations to address the issue of progressive collapse and promote building safety.

The wind turbine towers are essentially a multibody entity composed of rotor-nacelle assembly supported by a tubular tower that transfers the gravity load as well as the environmental load to the foundation. Several thin-walled steel tubes with flanges connected to form tubular steel towers. The records shows that most of the failure occurred at the bottom of the tube, and the major failure mode was local buckling. Thus, susceptibility to local buckling under compression and bending load accounts for the need for improved structural modification to the tubes of the wind turbine. The static analysis of innovative combined stiffened tubes was conducted by applying a constant axial force and varying lateral displacement. Different shapes of stiffeners, lengths of stiffeners, tubes with openings etc., were considered and the corresponding moment drift angle curve was generated. It was found that among all the considered specimens innovative modified steel tubes could greatly reduce the buckling deformation and increased both ultimate and failure loads. The static analysis of innovative combined stiffened tubes signifies a remarkable improvement in the ultimate moment of 42.85% was recorded and it was also found to be effective in controlling local buckling. The present study did not consider the connection between individual tubular units and residual stresses, apart from that modified steel tube was proven to be a feasible and efficient solution to control local buck-ling.

The theme of project aims to perform as well as the strength of a base isolation system for reference firm structures for the period of seismic events. The purpose of presenting a 3D referenced concrete frame building with safe position as a case study, using SAP 2000 software for modeling and analysis. Seismic load calculations can be performed according to IS 1893–2016 to meet earthquake-resistant resolution. This study addresses a 3-D reinforced concrete frame structure with dimensions of 21 m on the x-axis and 21 m on the y-axis, comprising a G + 6 configuration with a height of 24 m. The objective is to increase the natural time period, reduce level drift, and lower the acceleration response of seismic events. The paper evaluates the effectiveness of the base isolation system in terms of maximum shear force, maximum bending moment, base shear, level drift, and level relocation reductions.

The proposed research paper aims to examine the effects of different hybrid configurations and cutouts on the static and dynamic analysis of composite laminates. The study employs a 9-noded heterosis FE model to analyze hybrid composite laminates consisting of carbon and glass fibers arranged in various stacking sequences. The effect of varying cutouts on the stiffness and frequency of the laminates is also evaluated. The static analysis focuses on the laminate’s deformation under different stacking sequences, while the vibration analysis evaluates the laminate’s natural frequencies and mode shapes. The results obtained are compared to investigate the effect of different hybrid configurations and cutout sizes on the laminate’s performance. The research findings reveal that the hybrid configurations improve the stiffness and natural frequency of the laminates, while the cutout size has a significant impact on the vibration characteristics of composites. The study’s findings are also expected to provide insights into optimizing the hybrid composite laminates’ design for specific applications, where weight reduction and high strength-to-weight ratios are essential.

This research paper focuses on investigating the impact of localized damages on buckling behaviour of thin-walled slender RC columns. A FE formulation is developed to pretend the structural response of the columns under different damage conditions. The study aims to understand the impact of the location and size of the damage on the critical buckling load and the corresponding mode of buckling. The results reveal that the presence of localized damages significantly affects the buckling behaviour of the columns, causing a reduction in the critical buckling load and a change in the mode of buckling. The study also demonstrates that the type and location of damage are critical factors affecting the buckling behaviour of columns. The findings highlight the importance of considering localized damages in the design and analysis of thin walled slender RC columns.

To strengthen the existing vulnerable buildings, a variety of strategies and methods have been researched and put into practise recently. Stiffening already-existing structures and/or enhancing irregularities or discontinuities in the stiffness or strength distribution of a building are a few of them. Providing increased strength for the existing structures is the most promising job and to define a suitable strengthening technique needs a technical evaluation. RC (Reinforced Concrete) Jacketing is amongst the earliest and the most popular techniques used to retrofit or strengthen RC columns. In this paper, the seismic response of a 5 storey RC frame building before and after Reinforced concrete jacketing have been analyzed by adopting an incremental non-linear static analysis. Furthermore, change in ductility capacity and elastic stiffness has been evaluated with help of the obtained pushover curve and FEMA 356 coefficient method. The Elastic stiffness for both i.e., the original and the jacketed frame has been calculated by finding out the slope of the elastic region in the pushover curve. The capacity curve obtained from the analysis done in SAP2000, the behaviour of the frame was observed to be linear up to some initial values of the base shear post on which the frame displayed non linearity. It was also observed that after jacketing the columns of the frame, the load carrying capacity of the building has been increased tremendously. Similarly, the roof displacement also showed a significant increase.

Circular Hollow Sections are round tubular steel sections that are used for a variety of purposes in civil engineering. They are usually available in the market as hot-rolled or cold-formed sections. Hot-rolled circular hollow sections are usually employed for structural purposes such as columns, struts, ties, etc. Cold-formed sections are usually used as purlins and as framing for lightweight building construction. The Cold-Formed Steel Tubular column was tested for failure under axial compression. The parameters varied in this study are the slenderness ratio (24, 26, 28 and 30), the diameter of the tubular section (D1 = 76.2 mm and D2 = 3.3 mm) and retrofitting techniques (External Ring Stiffeners and GFRP strip wrapping). All the specimens were tested for failure by loading using Universal Testing Machine. The failure mode and load deflection behaviour was studied in detail. From the study, it was observed that the control specimen without the ring stiffener and GFRP strip wrapping with slenderness ratio 24 are found to be stiffer than other slenderness ratios. The increase in the D/t ratio from 31.7 to 38.1 increases the load-carrying capacity and overall behaviour of the tubular column. The analytical results are close to the experimental, but slightly less than the experimental results because of the rigid body connection.

The auxiliary building (AB) plays a crucial importance in the safety operation of nuclear power plants (NPPs). This study evaluates seismic performances of the primary auxiliary building in the Korean Standard (KS) nuclear power plants (NPPs). The numerical model of the AB structure is developed using a series of multi-layer shell elements, in which nonlinear material properties of concrete and reinforcement are considered. A set of 90 ground motions is employed in time-history analyses for evaluating the seismic performance of the structure. Floor accelerations and displacements of the structure are monitored as engineering demand parameters (EDPs). Statistical indicators including the goodness of fit (R2), standard deviation, and practicality are employed to evaluate the correlation between EDPs and 21 considered earthquake intensity measures (IMs). The results show that the strongest correlated IMs are $$S_{a} \left( {T_{1} } \right)$$ S a T 1 , $$S_{v} \left( {T_{1} } \right)$$ S v T 1 , $$S_{d} \left( {T_{1} } \right)$$ S d T 1 , followed by $$ASI$$ ASI , $$SMA$$ SMA , $$EPA$$ EPA , and $$PGA$$ PGA .

Concrete, comprising cement, coarse aggregate, fine aggregate, water, and admixtures, are extensively used in construction. However, exposure to high temperatures, like fire, can lead to detrimental changes in its properties, resulting in decreased performance or failure. This review offers an overview of the impact of elevated temperature on concrete, encompassing thermal cracking, strength reduction, and spalling. The mechanisms underlying these effects are examined, along with influential factors like concrete mix composition and heating rate. Several strategies to enhance concrete's fire resistance are discussed, including the incorporation of supplementary cementitious materials and fibers, as well as the application of coatings and surface treatments. The review concludes by highlighting the current knowledge in this field and identifying potential avenues for future research.

With increase in scale of road construction in India, it has become increasingly difficult to assess the timely completion of bridge construction. The major issue for delay is poor management of associated risks on projects. Moreover, the complexity of bridge projects further adds variety of risk factors. It is important to concentrate only on most significant risk factors which are having highest impact on timely completion of project. In this work the author brought an Analytical Hierarchical Processes (AHP) approach to identify most significant risk factors on bridge construction which are responsible for delay. Around 25 bridge case studies are considered for work. The long list of risk factors is formulated through repository of literature and bridge expert’s opinions. In the framework initially risk factors are divided in 3 level hierarchy for eliciting weightages. Then, the matrix is prepared using the pairwise comparison and the final weightages are obtained through AHP procedure. These weights are further used for prioritisation of risk factors. The main intent of this work to produce robust framework in prioritisation of risk factors predicted in bridge construction.

Concrete is now widely employed in the construction sector throughout the world because of its availability and affordability; however, it is prone to cracking. Due to water and chloride intrusion caused by cracking, which corrodes reinforced concrete's rebars, concrete's durability decreases. Additionally, it takes a lot of time and money to regularly evaluate and maintain concrete structures. Hence, A Critical Review of a Bacterial-Based Taxonomy for Self-Healing is most needed in the construction industry. Cracks can arise as a result of loading, volumetric change, extreme heat, creep, plastic resolution, contraction, or parameters of the system such as alkali-silicate response, freezing, and thawing cycles. Typically, slight cracks do not result in a building collapsing or impair its lifespan or sustainability. According to the study, a microbial self-healing technique is unique in that it has the ability to repair cracks quickly, effectively, and sustainably while also being ecologically friendly. In this section, a taxonomy of self-healing methods, including natural, autonomous (automatic and biological), and triggered healing processes, was constructed. The self-healing process is cost-effective for the building structure, but it relies on sustainable conditions like water and is less effective at fixing wider cracks. The biological approach was found to be promising because of the homogeneous properties of bacteria in the alkaline concrete environment.

Shear wall and bracing systems are most commonly adopted lateral load resisting systems in tall buildings. Shear walls and Bracings systems possess very high in-plane strength and stiffness, which can be simultaneously used to resist high horizontal loads and in turn support gravity loads, making them advantageous in many applications of structural engineering. The present paper focuses on study of building models (frames), bare frame model including shear wall and X and V type bracings system subjected to free vibration response using a horizontal shake table for experimental (using shake table test), analytical (using ETABS software) and theoretical solution. The building models SDOF and MDOF (G + 2 and G + 3) systems are subjected to free vibration to required amplitude to study the vibrational characteristics in terms of natural frequency and mode shapes. It is observed that the natural frequency values obtained for the model including shear wall and bracing systems are higher than that of bare frame models. Hence the presence of shear wall and bracing systems adds 20–35% stiffness to the building frames. Further it is observed that the X bracing system is effective in resisting lateral forces as compared to other types of bracing systems.

Stainless steel grades are emerging in industries due to their properties like resistance to corrosion, durability, weldability, minimal maintenance requirements, good aesthetic appearance, and ductility. Also, stainless steel can be recycled and is good fire resistant. Hybrid sections with a higher-grade flange and lower-grade web are used in construction to improve the stability of an I-beam. it is important to investigate the structural behavior of a hybrid stainless steel section containing perforations in its web because perforations are essential for the passage of building services like ducts for water, air conditioning, electricity, etc. A numerical investigation on the flexural behavior of perforated Hybrid Stainless Steel (HSS) I-beams using the commercial finite element software, ABAQUS is presented in this paper based on cross-section slenderness i.e., flange and web-critical sections. 3-point bending (3 PB) specimens were chosen for the current numerical investigations. The stainless steel varieties lean duplex stainless steel and duplex stainless steel are taken as the materials for the hybrid steel section.

This paper mainly deals with the effect of the non-dimensional slenderness ratio (λlt) on a member's ability to flexural behavior, which was studied numerically using a wide range of built-up I-sections. Axial, bending, shear, and torsional stresses are frequently present during a complicated loading condition that is applied to thin-walled frame parts with extremely narrow open cross-sections and poor torsional stiffness. As a result, they frequently experience instability even before reaching their production capacity. One of the most common types of lateral torsional buckling (LTB) is a prevalent instability phenomenon related to thin-walled constructions. The results are drawn to the conclusion that the design methodology was decided Instead of section classification, the non-dimensional slenderness ratio (λlt) determines the type of failure. The design procedure for the flexural design strength of the member, when the λlt ≤ 0.4 the yield stress governs the flexural design strength, it denotes that the component can form plastic hinges and has the necessary rotational strength for the structure to fail due to the development of plastic mechanism. When the λlt > 0.4 then the flexural torsional buckling strength governs the design bending strength, which means the member can’t develop plastic hinges and the member failed before the process of the plastic mechanism’s creation. As a part of the research, we are focusing on how the non-dimensional slenderness ratio affects the flexural capacity of a member. It was observed that even though the section was under the plastic section and compact section, the member failed before reaching its yield stress.

One of the largest and most crucial components of a building’s structure is the floor slab system. Primarily, slabs are designed to support gravity loads, whether they are used to build a basement floor, a ground floor, or at upper floor levels. The slab thickness will play a vital role in building aesthetics, architectural aspects, design, cost, and construction. The increased slab thickness will lead to increased self-weight and material quantity, and thus affect the economy. This study attempted to evaluate the performance of different floor slab systems for commercial structures under gravity loads, including conventional slab-beam systems, RC flat slabs, RC band beams, and bonded post-tensioning slab systems. The structure consisted of a ground floor with ten floors and a terrace. The standard typical floor size of the structure is 1600 m2. The analysis and design of the structural floor slab systems were performed using applications, and the findings were validated manually in accordance with the prevailing standards. The results reveal that the PT slab has a higher strength capacity over other slab systems and performs better under serviceability and strength conditions. However, PT slab requires a slender section with less material consumption along with more structural performance than other slab systems for commercial buildings.

To date, numerous investigations have been conducted on supplementary cementitious materials (SCM'S) to enhance the properties of concrete. These SCM’S not only decreased cement and aggregate consumption but also lowered the environment issues. This research conducted the study on the ternary combination of sugarcane bagasse Ash (SCBA), Jute Fibre (JF) and Nano alumina. The focus of the current study is to investigate the mechanical properties of concrete on replacing cement with different percentages of bagasse ash (0, 5, 10, 15 and 20%). Jute Fibre proportions were utilized as 0.15, 0.25, 0.35 and 0.45% for partial replacement of cement at optimum dosage of bagasse ash (BA). Compressive strength [CS], [STS] Split tensile strength, and [FS] flexural strength of the hardened composites were examined. To investigate the further improvement in strength properties of concrete, Nano Al2O3 percentages of 0.75, 1.75 and 2.75% were incorporated into the Mix by volume of mortar. A water-cement ratio (0.4) was held constant. The findings showed that 1.75% Nano alumina based concrete with 10% Bagasse Ash and 0.25% Jute Fibre outperforms all other concretes in terms of strength characteristics.

The study investigates experimental and analytical behaviour of fiber reinforced concrete deep beams with and without circular opening for ultimate load and crack patterns. Generally deep beams are having overall depth and effective depth (L/H) greater than 2 or 2.5 for simply supported beams and continuous beams respectively. Deep beams are used in a variety of construction structures, including wall footings, transfer girders, basement pile caps and shear walls. The utilization of a deep beam at the lower level of tall structures for both residential and commercial purposes, in particular has expanded fast. In this study twelve deep beams are casted with different combination of materials like without flyash, with flyash, with flyash and fibre and with Circular opening of diameter 60 mm. Casted Beams were tested under two-point load system for ultimate loads. Results of experimental test determine that providing of opening leads to an increase in failure load. The crack patterns of the beam were observed and results are compared with analytical results obtained in ANSYS 2022 R2 software.

The behaviour of a fibre-reinforced concrete deep beam with and without an opening under two-point loading is presented in this study. A total of twelve deep beams with dimensions of 700 × 350 × 150 mm were cast, three of which are traditional deep beams and other deep beams with different combinations like 30% replacement of cement with flyash, with flyash in addition with fibre, with flyash and fibre and rectangle opening of size 60 × 40 mm. Two rectangular openings, one each in the shear span of the beam were placed symmetrically at a distance of 145 mm from soffit of the beam to the centre of opening. From the experimental test results, it was observed that the addition of fibre leads to significant increase in failure load. It is also noticed that the opening disrupts the crack pattern by deviating the natural load path of the crack, which helps to increase the load bearing capacity of the beam with ultimate load of about 485 kN. The study also extends to determine the behaviour of deep beam by numerical analysis using ANSYS Program. The crack patterns of the beam were examined, and the patterns were very near to the analytical results obtained in ANSYS.

Reinforced steel corrosion in concrete and masonry buildings is so common that it has earned the moniker “Concrete Cancer” to describe the phenomenon. Corrosion causes many cracks and concrete spalling, eventually bringing down the lifetime of the building. RC buildings are more expensive to repair and maintain, and the resulting vibrations can be harmful to the sustainability of the remaining structure. Taking measures to reduce corrosion, such as raising the cover or applying anti-corrosion coatings, will result in larger section sizes, higher construction costs, and weakened bonds. Stainless steel is used as reinforcement because it is more corrosion-resistant, has a longer lifespan, and requires less maintenance. In comparison to regular steel, it has improved ductility and strain-hardening capabilities. While the cost of this stainless steel may be higher than that of mild steel at the outset, it will require far less upkeep over time. Compared to conventional RC buildings, the lifespan of those made with stainless steel reinforcement is doubled. More study is being devoted to this stainless steel-reinforced concrete because of the current emphasis on “Sustainable infrastructure.” This paper provides a concise overview of the material and structural features of SSRC, an in-depth examination of the already available data, and a discussion of where further study is needed.

It takes a lot of energy to produce ordinary Portland cement (OPC), a key component of concrete, which results in a significant amount of carbon dioxide and other greenhouse gases (GHGs) being released into the environment. Alkali-activated composite (AAC) paste phase is a key factor in defining the mechanical characteristics and durability of these environmentally friendly alternative binders. The paste phase in AACs is thoroughly discussed in this work in terms of its composition, microstructure, and performance traits. Investigation is conducted into the effects of numerous variables, such as precursor composition, curing circumstances, alkali activator concentration (in %), on the qualities of the paste phase. Additionally, the microstructural analysis is carried to give light on the mechanisms underlying the AACs’ mechanical toughness and durability. The findings support the development of environmentally friendly and high-performing building materials by advancing our understanding of and ability to optimize the paste phase in AACs. It was determined that the ideal combination for an alkali-activated composite in its wet form was 6% Na2O and 10% SiO2. The results observed when the curing temperature was varied from 50 to 90 °C were around 68.06 MPa for 6% of Na2O content at 70 °C and 70.07 MPa for 10% of SiO2 content at 90 °C.

Axisymmetric shell structures are generated by rotating plane curve around its axis of rotation to form a circumferentially closed surface and are generally used for hyperbolic cooling towers. These are thin shell structures possessing adequate strength and aesthetically pleasing. Considerable research on the behavior of cooling towers is available in the literature since the development in the finite element method. The present work investigates the free vibration analysis of shell on fixed base and column-supported cooling tower shell using ANSYS software. The study on modes of vibration (first lateral mode, torsion mode) and behavior of tower shell in circumferential mode (n) 1, 2, 3, 4, 5, and 6 for Meridional Mode (m) 1, 2, and 3 are observed for shell on fixed base and column supported shell for different uniform shell thicknesses. The analysis results revealed that natural frequency of the first lateral mode is unaffected by change in the shell thicknesses, but it occurs earliest in the thickest shell. Influence of shell thickness on torsion mode was observed to have no significant change except change in mode number. The study of circumferential mode (n = 1, 2, 3, 4, 5, 6) for Meridional mode (m = 1, 2, 3) for shell on fixed base with varying different uniform shell thicknesses (Uniform along the height) revealed that the frequency values alter for circumferential mode (n ≥ 4) greater than or equal to 4. The study of circumferential mode (n = 1, 2, 3, 4, 5, 6) for the Meridional modes (m = 1, 2) for column supported shell with varying different shell thicknesses (Uniform along the height) revealed that the frequency values alter for circumferential mode (n ≥ 1) greater than or equal to 1.

With increasing population in developing countries, and scarcity of good land for construction high rise building have become a vital alternative. As the height of building increases, wind load becomes a vital parameter to be considered for an analysis and design of high-rise structure. In this work, G + 40 building is analysed for wind loading by varying the wind zones and construction material, i.e., RCC and steel in all four terrain categories. In all 48 models of the building are analysed using ETABS v20 and the wind load is applied using IS 875 (Part 3) 2015. The result obtained is plotted in bending moment, storey drift, displacement..

Incorporating extra materials called admixtures is one of the major ways researchers have been using to produce concrete that can overcome adverse exposure conditions. In this light, this study experimented with the combined usage of Metakaolin (MK) and Ground Granulated Blast-furnace Slag (GGBS) by partially replacing cement at 40%, 50% and 60% and maintaining water to cementitious content (w/cm) at 0.45 to know to what extent can cement be replaced by this blend to give better durability performance without compromising the strength. The experimental program included tests on concrete durability properties such as water absorption, permeable void and sorptivity as well as compressive and flexural strength of concrete exposed to artificial saline water. This study found out that samples with 40% cement replacement by 30% GGBS and 10% MK performed better than other partial replacement levels in regards to compressive strength (31.56 MPa) and the overall durability properties investigated (5.73%, 16.86%, 0.0209, 0.00243 for water absorption, permeable void, primary sorptivity and secondary sorptivity, respectively). The samples with 60% cement replacement having 40% GGBS and 20% MK gave the best resistance to primary sorptivity (0.01801) but had the worst performance for compressive strength (16.14 MPa) in saline water. It is concluded that replacing cement by combining MK and GGBS can give satisfactory performance for durable concrete in Marine Environment, however, the partial replacement of cement should not be more than 40%. Incorporating GGBS and MK has environmental benefit as they are waste materials and their usage should be encouraged.

The alkali-activated concrete (AAC) is an ecofriendly alternative to ordinary Portland cement (OPC) concrete. AAC reduces carbon emissions by the usage of aluminosilicate materials instead of OPC. The buildings and other concrete structures can be exposed to acids throughout its service life, especially in marine buildings, factories, agricultural, and sewage components. This study aims to the comparison of resistance of AAC and conventional mortar towards sulphuric acid (H2SO4) attack. The materials used for the preparation of AAC mortar specimens are cementitious components and alkaline activators. The cementitious components are GGBS and fly ash as the binding material of ratio 1:9. The alkaline activators used are sodium hydroxide (NaOH) solution of 8 M and sodium silicate (Na2SiO3) solution, which has a ratio of 1:2.5. Sulphuric acid of 98% assay is used for preparation of the 5% acid solution. Totally, 9 cubes for AAC and 9 cubes for OPC mortar specimens of size 7 cm × 7 cm × 7 cm were prepared and the specimens were shifted to H2SO4, and the changes have to be observed by visual appearance, mass loss, volume change, pH value, and compressive strength test at the age of 1-month duration. The results suggest that alkali-activated mortar specimens show better performance than OPC mortar specimens.

In the actual world, conventional curing techniques usually fall short. Water evaporation is typically reduced even when precise management methods are employed, but excess water on vertical structural elements is still a problem. To achieve the necessary attributes in conventional concrete buildings, the procedure of strength-gaining is essential. To acquire the necessary strength, concrete must cure for 28 days with the proper amount of water. Poor curing can reduce a material's strength and longevity. Self-curing is a modern technique for curing concrete that, because of the moisture content, fixed itself. When polyethylene glycol is utilized in conventional with recycled concrete, the ingredient helps to maintain optimum hydration. It helps in the manufacturing of water-soluble emulsification, detergents, plasticizing agents, and textile lubrication. In the current experiment, polyethylene glycol-400 addition in recycled concrete would result in strength. The adoption of alternative materials quickly lowers the cost of construction. For concrete to self-cure, it was proposed that polyethylene glycol PEG400 chemical be added. In this study, the relationship between PEG400 in addition to cement—which varies from 0 to 1.5% by weight—and self-curing concrete is examined. The research aims to use polyethylene glycol-400 (PEG400) as an additive in recycled concrete to achieve self-curing properties. Self-curing concrete is a modern technique that eliminates the need for external curing methods by maintaining its own moisture content. This indicates the effectiveness of PEG400 in enhancing the overall structural performance of recycled concrete. The research gives a distinctive viewpoint on tackling the issues of water shortage, strength development, and cost-effectiveness in the construction sector by concentrating on the application of PEG400 in self-curing concrete using recycled components.

The bamboo used in construction is widely known and well-established in rural areas. Also, using bamboo as a concrete reinforcement member can minimize CO2 emissions of steel-reinforced concrete members. This study used bamboo that had already been pre-treated with epoxy resin and subjected to sandblasting to increase friction between the bamboo and cement mortar. In addition, tests were performed on the flexural and durability of the bamboo-reinforced concrete beams. Compared to steel–concrete beams, the failure mechanism of reinforced concrete beams is not considerably altered when bamboo reinforcement is used instead of steel reinforcement in concrete. However, the initial crack load showed better results. The transverse loading tests are carried out on plain, steel, and bamboo-reinforced beams to assess the ultimate load, deflection, and failure mode pattern. Moreover, durability tests are performed on beams to examine how they respond to various exposure conditions. These experiments indicate that bamboo may replace steel as a beam-reinforcing material with proper pretreatment for low-cost construction buildings.

Concrete is increasingly being used in the industrial sector. Carbon dioxide (CO2) emissions are increasing as a result of the use of concrete. Limestone Calcined Clay Cement (LC3) is one such alternative discovered by researchers to reduce CO2 emissions and safeguard the environment from being polluted. LC3 is ternary blended cement prepared by 50% clinkers, 30% calcined clay, 15% low grade limestone and 5% gypsum. Agricultural waste disposal, such as coconut coir fibres, also pollutes the environment. So, in this study, M25 grade concrete is made by combining LC3 with Coconut coir fibre. Coconut fibre percentages such as 0.3, 0.6, 0.9, 1.2, and 1.5 were utilized to estimate compressive and flexural strength on both LC3 and normal concrete. The result shows that using 1.2% coconut fibre has better strength properties compared to other mixes. The use of coconut fibre decreases the workability of concrete. The microstructure of M25 grade of concrete was observed by Scanning Electron Microscopy (SEM) analysis.

Concrete is an extensively used material in the construction of structures. Ordinary Portland cement which is used in concrete emits lots of carbon dioxide. Production process of OPC alone contributes to 3% of world pollution. To drop the usage of cement and also for the use of by-products from various industries alkali-activated concrete (AAC) is used by replacing the cement with industrial by-products and using alkali activators, i.e., NaOH, Na2SiO3. The present study focuses on the mechanical and thermal properties of the alkali-activated concrete (AAC) with GGBS and fly ash as binders with NaOH and Na2SiO3 as activators and replacing fine aggregate with quartz sand.

Masonry constitutes masonry units and mortar. Masonry carries predominantly compressive forces and the compression strength of a prism mainly depends on the strength of the masonry units and it is less sensitive to the strength of the mortar. Literature reveals that the compression strength increases with an increase in bond strength. So an attempt is made to study the effect of an increase in the strength of mortar and bond strength by using commercially available cementitious grouting material as mortar in order to achieve the requirement. Five brick height masonry prisms corresponding to the height-to-thickness ratio (h/t) of 3.95 is used to ascertain the compressive strength at 3, 7, and 28 days. The mortar joint thickness was limited to 5 mm with grouting material as mortar, with the intention of faster construction. The compression test results are compared with the conventional mortar of 1:3. The results such as compressive load and strain were ascertained in the saturated condition. Masonry prism with conventional mortar showed more brittle failure than grouting material as mortar.

This paper presents an experimental investigation of the flexural and shear bond strength of the masonry prism. The masonry prisms were constructed in triplet prisms for the shear bond strength test and five levels of stack-bonded prisms for the flexural bond strength test. The bond characteristics of masonry depend on the mortar type and the surface texture of the masonry unit used. To increase the flexural and shear bond strength present work is carried out by using cement concrete bricks as masonry units and grouting materials as thin layered mortar. Most of the work is done on the conventional mortar of 10–12 mm thick however 1–5 mm thick masonry bond is not yet well researched, hence 5 mm thick mortar joint is used for both flexural and shear bond strength for 3, 7 and 28 days and is compared with conventional cement mortar of 1:3 ratio of 10 mm thickness. Reduction in the thickness of mortar joints helps in a faster rate of construction. The results reveal higher bond strength for cementitious grouting material as mortar.

More than ever before, there is a growing need for extending the service life of existing structures by means of retrofitting or rehabilitating given the rising scarcity and increasing costs of raw materials for reconstruction on one hand and on the other, to reduce the emission of greenhouse gases involved in the production of raw material used for construction. Strengthening of existing structures is one way through which the above predicaments can be addressed. In this experimental study full scale RC beam models of size (3000 × 150 × 175)mm of M20 grade concrete were considered to be strengthened for shear with near surface mounted (NSM) GFRP strips and understand the performance of the beam element. GFRP strips were embedded using epoxy in the grooves cut on the side faces of the beam oriented at 45° angle with respect to the beam axis and tested for single point loading. Load–deflection relationship of beam, ultimate load carrying capacity, cracking pattern and mode of failure were the findings of this experimental study.

Alternatives to cement are widely used in concrete technology. Despite the fact that many researchers have looked at the characteristics of concrete after adding mineral admixtures. A “binary blended cementitious system” with RM and SM modified from 0–20 percent by an increment of 5% produced twelve alternative mix proportions. This study compares the binary cementitious systems of mechanical properties (compressive, flexural and split tensile strength) in order to determine the optimum percentage of materials, such as red mud (RM) and silica fume (SF) with manufactured sand (M-Sand) at the ages of 7, 14 and 28 days. The designated test result will include any mineral admixtures, which will generally have an impact on the mechanical characteristics of all the tested specimens. The combined use of red mud and “silica fume” concrete mix slightly improves the mechanical properties compared to the alternative studies, although red mud is less effective than silica fume. The use of additional cementitious materials with mineral admixtures increased strength increases up to 10% replacement of RM and SF, it is concluded. When compared to the findings of the experiments, the proposed regression equations produce relatively minor errors; as a result, they are capable of producing predictions of the flexural, split and compressive strengths that are accurate and efficient.

Stabilized Geopolymer mud blocks were produced by compacting a mixture of mud as aggregate and fly ash as binder with an alkaline solution made of sodium silicate and sodium hydroxide in a block making machine. The blocks were cured at ambient temperature and were tested for water absorption, initial rate of absorption, dimensionality, density and compressive strength at different ages. Mortar is the one which bonds two masonry units together so they function as a single unit in the structure. In this paper, the performance of stabilized geopolymer mud block masonry strength with various types of mortar like cement mortar, cement-soil mortar, fly-ash-based geopolymer mortar at various ages was studied. Geopolymer mortar with its good compressive strength proved to exhibit promising properties compared to cement mortar and cement soil mortar and hence, suitable in masonry construction. It was found that the stabilized geopolymer mud block also developed significant strength and was found to be suitable for the construction of load bearing masonry structures. The basic properties of stabilized geopolymer mud block masonry was well within the limits prescribed in the relevant IS codes. Better load carrying capacity and crack propagation were observed while testing the masonry prisms. The study proves that the stabilized geopolymer block masonry can be efficiently used as an alternative building material which at a global economy accounts to reduction in the use of cement and cement products as building materials, and reuse of waste materials like fly ash and hence be eco-friendly.

This paper presents the development of Fiber Reinforced Concrete (FRC) using carbon fibers for the application of sluice gates in small dams. This study aims to investigate the mechanical properties of the developed FRC and compare them with the properties of conventional concrete. The study also aims to evaluate the durability of the FRC against water erosion and abrasion. Carbon fibers were chosen as the reinforcing material due to their high strength, low weight, and corrosion resistance and as a sustainable alternative to traditional reinforcement materials like steel fibers. The methodology involves the use of carbon fibers as a reinforcement material for concrete mixtures. A series of concrete samples were prepared with varying percentages of carbon fibers, and their mechanical properties were evaluated through standard testing procedures. The results showed that the developed FRC having 0.5% fiber had superior mechanical properties compared to conventional concrete. The compressive strength of FRC for 28 days is 64.761 N/mm2 whereas that of the conventional concrete is 41.640 N/mm2. The tensile strength of the FRC is 3.40 MPa whereas that of the conventional concrete is 2.303 MPa, the findings of this study demonstrate the potential of using carbon fibers in FRC for the application of sluice gates in small dams. The implementation of automation in the operation of the sluice gate at various conditions has been done.

The usage of traditional coarse aggregate in concrete production has been associated with several environmental issues like carbon dioxide emissions, waste disposal problems, and natural resources depletion. This has sparked a growing fascination with developing sustainable alternatives to traditional coarse aggregate. Hemp shives, which are leftovers from hemp plants, have been suggested as a potential substitute for coarse aggregate in concrete. Present investigation aims to research the mechanical and durability properties of concrete produced with hemp shives as coarse aggregate. In the present study, the experimental investigation is done in hemp concrete of M25 grade. Hemp shives are utilized to partially replace coarse aggregates by 5, 10, and 15% respectively. The influence of hemp shives on mechanical (split tensile strength, compressive strength test, and flexural strength) concrete's characteristics were noticed and the durability (Water penetration depth, Sorptivity) was also examined. Hemp Shives mineralized with aluminium sulphate and calcium hydroxide before using it as coarse aggregate in concrete mixture. The Aluminium sulphate: Calcium hydroxide ratio is 1:2 and cement is replaced by 10% using Fly Ash. The Compressive Strength specimens had been investigated for 7 days and 28 days while split tensile, flexural strength, water penetration, sorptivity were investigated at 28 days. It is found that the compressive, split tensile, and flexural strength was gradually decreased with increasing Hemp Shives percentages by coarse aggregate replacement. However, strength and durability tests for 5% replacement of coarse aggregate with Hemp Shives give a comparable result. The use of hemp shives in concrete production can significantly reduce the environmental impact of concrete production and provide a sustainable alternative to traditional coarse aggregate.

High-performance concrete known as self-compacting concrete (SSC) may flow effortlessly under its own weight without the use of mechanical vibration. Due to its excellent qualities, including filling formwork and self-consolidating, it is frequently used in construction. The study's objective is to determine the ideal chemical admixture percentages for composite SSC. 40% of GGBS, 30% of GGBS, 20% of GGBS and FA, 15% of GGBS and FA, 40% of FA, and 30% of FA were replaced for various amounts of GGBS, FA, and cement. The Bureau of Indian Standards (BIS) SSC was examined for strength, flexural, and split tensile strength behaviours at various ages for varied cement replacement amounts, and the outcomes were compared to conventional SSC (100% cement). Armix-HyyeCrete PC 20 super plasticizer has been utilized to ensure workability while maintaining a steady water-binder ratio. To improve strength and durability, the paper's conclusion emphasized the significance of determining the ideal amount of chemical admixture in composite SSC. Doing so might potentially lower the cost of SCC and make it more commercially feasible for usage in construction.

Provision of openings in reinforced concrete beams is normally required to provide essential services. Most likely, the circular openings are provided to pass through service pipes, such as plumbing, whereas air conditioning ducts are generally rectangular in shape. These beams have two main benefits namely reduction of self-weight and accommodation of service line. The present study deals with the trials conducted on a total of seven different types of beams (each type three numbers) that included one solid control beam, three beams without Carbon fiber reinforced polymer (CFRP sheathing and three beams with CFRP sheathing for rectangular, rounded rectangular and elliptical openings. The outcome of ultimate strength of the beam with opening and supported by CFRP sheathing is highlighted in this paper. From the load vs deflection curve, it can be understood that beams sheathed with CFRP behave similar to that of reference/control solid beam (SB). On an average 7% of concrete can be saved by providing opening in beam, which will ultimately reduce its weight and load on foundation.