Ductile Detailing Research Articles

A simplified procedure for seismic collapse probability assessment of RC frame buildings

AbstractThis paper presents a procedure for simplified collapse probability prediction of RC frame buildings when subjected to ground motion intensities commonly used in designing buildings. For this purpose, seismic collapse probability of a range of RC moment resisting frame buildings are assessed at the design basis earthquake (DBE) and the maximum considered earthquake (MCE) levels of seismic intensity by conducting more than a thousand nonlinear response history analyses (NRHA) using a suite of 40 seismic ground motion records. The 13 buildings included in the investigation have different heights (5–15 storeys) and footprints (3–6 bays), are designed to different target maximum inter‐storey drifts (within the code specified limit), and have critical members detailed to sustain different levels of confinement and anti‐buckling demands. The NRHA results consistently demonstrate that the design inter‐storey drift and the anti‐buckling detailing of longitudinal rebars in the critical frame members strongly influence the collapse probability of RC frame buildings. The results also show that while RC frame buildings designed to reach 2.5% (or less) inter‐storey drifts and detailed for ductile seismic performance can successfully avoid collapse at DBE, avoidance of collapse at DBE cannot be guaranteed if RC frames are designed to reach a target drift of more than 2% and not detailed for full ductility. At MCE, collapse probability is found to consistently exceed 10% unless the building is designed to incur no more than 1% plastic drift and the frame members have ductile detailing. Based on the NRHA results of the 13 case study buildings, easy‐to‐use equations relating their seismic collapse probability at MCE with the design drift and a quantifiable measure of ductile detailing are generated and validated by comparing with the collapse probability obtained by NRHA of an independent RC frame building. The proposed equations provide a rapid, yet reasonably reliable tool for performance‐based seismic design of RC frame buildings, and enable designers to estimate seismic collapse probability of RC frame buildings without having to conduct cumbersome NRHA.

Seismic vulnerability assessment of RC deck-stiffened arch bridges

Due to the recent damage and collapse of several bridges in Italy, reliable quantification of their vulnerability is paramount for planning various risk mitigation and resilience-enhancing strategies. This paper specifically focuses on the seismic vulnerability and loss assessment of existing reinforced concrete (RC) deck-stiffened arch bridges. The study considers a bridge typology known as the “Maillart–type” arch bridge, a common structural typology in the 1950s and characterised by a particularly stiff deck and a slender vault, i.e., a high deck-to-arch flexural stiffness ratio. Such bridges were typically designed considering only gravity loads and usually without ductile structural detailing and consideration of capacity-design principles. Historical documents and original design blueprints are used to simulate the design of an archetype bridge representative of the Italian “Maillart-type” arch bridge population. Then, nonlinear cloud-based time-history analysis is performed to investigate the seismic response of the considered archetype under varying ground-motion intensities and derive fragility and vulnerability relationships. Specifically, three different models are considered: one that adopts a conservative approach where damage is determined by the shear failure of the shortest pillar, another that provides a more detailed representation of structural damage progression, and a third that assumes retrofitting of the shortest pillar. The vulnerability relationships are combined with site-specific seismic hazard curves for case-study locations to estimate expected annual losses. The results represent a first step in assessing the seismic vulnerability of “Maillart–type” arch bridges to plan seismic risk mitigation interventions for such a bridge typology.

In-plane behaviour of masonry infill walls with openings strengthened using textile reinforced mortar

A numerical study was carried out to simulate the in-plane behaviour of a 1:2.5 scaled one-storey one-bay masonry-infilled reinforced concrete (RC) frame retrofitted with textile-reinforced mortar (TRM). The study used ABAQUS finite element analysis (FEA) software and a three-dimensional (3-D) finite element method. Using a ductile design and details, the TRM-reinforced structure encountered in-plane displacement-control cyclic loads during the test. This study assesses how accurately a representative numerical model can replicate the results of an experimental test. Parametric research was conducted following the numerical model's calibration. To develop a suitable numerical model, suitable constitutive models based on the concrete damage plasticity (CDP) approach were used to characterize the nonlinear response of TRM, masonry infill, and concrete. The experimental findings, which aggrandize the response simulation, served as the basis for calibrating the models. Using a finite element framework and the simplified micro model technique, the masonry structure is simulated at the infill component level. The numerical model demonstrated accurately the ability to simulate the in-plane behaviour of the modified RC frame with infill walls, including its initial stiffness, deterioration, deformation-resisting ability, and failure patterns. Furthermore, a parametric study was conducted to determine the significance of the full-bond scenario between the RC frame infilled with masonry and the TRM considering: (1) the location of the strengthening material on the specimen and (2) the number of layers of the strengthening material. All retrofitted wall specimens showed a considerable improvement in in-plane performance; some features of the wall's behaviour were found to be strongly influenced by the parameters under examination. It can be observed that the specimen with two layers of TRM on both sides of the infill wall exhibit the maximum lateral load carrying capacity and maximum deflection resisting characteristics while the other retrofitted specimens controlled the deflection to some extent and significantly enhancing the load carrying capacities of the masonry system.

Ductile Behaviour of Fiber Reinforced Self Compacting Concrete Beam with Alternative Detailing

Self-compacting concrete is one of the major advancements in construction. The purpose of this investigation is to evaluate how self-compacting concrete with steel fibres and the appropriate superplasticizer for M30 grade is presented. Effects of combining quartz flour 0 %,5 %,10 %, 15 %, 20 % and steel fibre 0 %,0.25 %,0.50 %,0.75 %, 1 % in varying amounts adding with cement. An experimental study was conducted on the fresh and hardened states of concrete. The optimal combination of quartz flour and steel fibre reinforced concrete was discovered while comparing the mixes to conventional concrete. Quartz flour with ultra-fine particles can fill holes and improve permeability resistance as well as bonding. As a result, utilizing this combination of quartz flour in self-compacting beams, studies explored the strength and ductile properties of normal and ductile details in beams, as well as comparing them to standard self-compacting concrete. Because self-compacting concrete is brittle by nature, adding fibres increases its tensile strength and ductility. Mineral admixtures improve the flow qualities.

Performance-based wind and earthquake design framework for tall steel buildings with ductile detailing

According to the Canadian building code, wind design relies on prescriptive static methods, which lead to a conservative design. In consequence, in moderate seismic regions where both winds and earthquakes are critical, the size of ductile members resulting from seismic design, and especially those of bottom floors, may not accommodate the elastic wind demand and larger member sizes are required. In general, this is the case of rectangular buildings, where in the direction perpendicular to the largest building dimension, the base shear due to elastic wind demand is critical, while in the orthogonal direction the seismic demand governs. Hence, in one direction, the allowable base shear increases above the seismic demand, which results in reduced energy dissipation and amplification of torsion. To mitigate the incoherence in the current building code, a refined code-based multi-hazard design approach, targeting performance of tall steel buildings in Eastern Canada, is proposed. Thus, accounting for the building’s overstrength and allowing limited controlled inelasticity under high-intensity wind, a wind-related reduction factor RW is proposed to reduce the design wind load. The method is implemented for the design of two identical 15-storey steel braced frame buildings, but of different occupancy, hospital and office, respectively. Nonlinear response history analyses are performed to verify the member sections of steel braced frames, while the parameters investigated are the interstorey drift, residual interstorey drift and floor acceleration. Then, seismic and wind incremental dynamic analyses provide insight into the multi-hazard dynamic response of buildings subjected to ground motions and winds of increasing intensity. The fragility concept is used to quantify the performance of studied buildings designed with RW = 2 versus the building designed with RW = 1. Comfort criteria, as well as, the drift acceptance criteria, commonly considered in research and practice, are used to verify the effectiveness of the proposed method. The nonlinear response of the studied buildings at the design level and beyond shows that using RW = 2 for wind design does not change the response at design level, but slightly decreases the collapse capacity within the acceptable range.

Behavior of Flood Resistant Building and Ductile Detailing of G +7 RC Building Using IS 13920-2016

Floods are one of the most widespread and destructive natural disasters occurring in the world and with the increase in constructions along river courses and concentration of population around floodplain areas, flood-induced damages have been continuously increasing. The annual disaster record reveals that flood occurrence increased about ten folds over the past five decades. Thus, floods are posing a great threat and challenge to planers, design engineers, insurance industries, policymakers, and to the governments. Structural and non-structural measures can be used to deal with floods. Structural measures include a set of works aiming to reduce one or more hydraulic parameters like runoff volume, peak discharge, rise in water level, duration of flood, flow velocity, etc. Non-structural measures involve a wide range of measures to reduce flood risk through flood forecasting and early warning systems, emergency plans, and posing land use regulations and policies. The futuristic reinforced concrete buildings can be considered as a symbol of modern civilization. These buildings are usually constructed based on the guide lines given by the standard code books(like IS: 456:2000 and IS 13920:2016).Unfortunately, the code provisions consider the seismic loads and wind effects alone, while accounting the dead and live design loads, and exclude the flood loads. This implies the necessity to bring out corrective measures that can be adopted to reduce vulnerability before harm occurrences. In this project focuses on both the incorporation of flood loads during the analysis and design in CSI-ETABS software and the assessment of flood vulnerability of reinforced concrete residential buildings. Vulnerability is expressed as a fraction of ground floor height and maximum flood level at most immerse the building up to ground floor and first floor level. The importance of the outcome arises from the need of a strengthening solution to avoid failure of new or existing structures during floods.

Performance Assessment of Ductile Detailing Code-Based Reinforced Concrete Special Moment Resisting Frames

Reinforced concrete (RC) buildings make up the majority of Indian building stocks. Structural elements of these buildings are often designed limited to non-ductile detailing. With a very low building replacement rate, many Indian buildings are vulnerable to earthquakes and pose a significant risk to lives, properties and economic activities. This paper examines the effectiveness of ductile-detailing in mitigating the seismic collapse risk by analyzing the behaviour of a four-storey RC Special Moment Resisting Frame (RC SMRF) using the latest codes of ductile detailing. It also aims to quantify the impact of lateral force resisting system detailing on the performance and cost of RC SMRF buildings and its benefits. The present study emphasizes the effect of ductile detailing on three fundamental aspects of the structure – safety, stability and economy. Two four-storeyed building models – one without ductile detailing and the other with ductile detailing are designed and then analyzed using non-linear static analysis. The results of this study represent the behaviour of ductile-detailed and non-ductile-detailed buildings in terms of pushover curves, and hinge behaviour and identify the mode of final failure. In extension to that, a cost-benefit analysis is done to study the benefits of ductile detailing with the increased cost. The marginal increase in initial cost associated with ductile detailing is significantly outweighed by the resulting savings in the repair and downtime costs during the service life of the building.

Comparative Analysis of Multistorey RCC and Semi-Rigid Steel Frame with Cross Bracings Subjected to Mainshock and Aftershock Earthquake Sequence

Strong Ground Motions have a significant impact on structural analysis and design. Seismic evaluation is deemed necessary for the quality, reliability, and feasibility of existing and developing structures. Earthquakes are even more disastrous when a mainshock is succeeded and preceded by aftershocks of higher magnitude. Most of the time, these aftershocks are ignored during analysis. In the last few decades, steel buildings have been crucial to the construction sector. On the other hand, RCC frames are commonly designed structures for commercial purposes and cost-effectiveness. IS 1893 (Part:1)-2002 Criteria for Earthquake Resistant Design of Structures and IS 13920-2016 Ductile Detailing of RC Structures Subjected to Seismic Reactions are majorly used for Seismic Analysis. Steel bracings in the structural system increase the ductility and stiffness of the frame structure. That can be arranged in a variety of ways, such as X, diagonally, alternatively, V, inverted V, K, etc. Cross bracings are used in this paper for the design of a typical multi-story (G+9) semi-rigid steel frame and a typical RCC frame is designed of the same dimensions. Both the frames are modelled and compared using ETABS software and a static nonlinear Time History analysis is executed to examine the performance of both the frames under the Mainshock and Aftershock of Chamoli earthquake. The Mainshock and Aftershock results of the Chamoli earthquake are extracted from the Centre for Engineering Strong Motion Research Ground Motion Database. Base shear, joint displacement, kinetic energy, and story displacement are a few of the variables of Time History Analysis that affect how well a building performs during mainshock and aftershock earthquakes. When analysing the outcomes, it is important to take into account that each of these factors significantly affects how a building responds to seismic loads.

Behaviour of Intermediate Moment Resisting RC Frame Structures Under The Influence of P-Delta Effect

Among the different categories of RC frames based on the implemented ductile detailing of the members, Intermediate Moment Resisting Frame (IMRF) is imparted with medium ductility capacity. Buildings with IMRF are intended to be used in Indian Seismic Zone III which refers to moderate level of seismic risk. Although past research has focused extensively on seismic behaviour of non-ductile and fully ductile moment resisting frames, very few studies on IMRF behaviour have been carried out. Also, the influence of P-Delta (P-?) effect on nonlinear behaviour of RC frame buildings has been studied to a limited extent. The present study aims to study the influence of imposed displacement pattern on the nonlinear behaviour of IMRF considering the P-? effect. Initially, single RC frame building five-storey with symmetrical floor plan, is designed as per the relevant Indian guidelines considering possible IMRF behaviour. Although the detailing of frames with medium ductility is absent in the current Indian Code IS: 13920-2016, the same has been carried out as per the draft IS: 13920. Displacement-controlled nonlinear static analysis or pushover analysis is carried out for the designed frames. For the distribution of imposed displacement pattern along the height of the frame, 4 different profiles are adopted, namely (a) parabolic as per IS: 1893 (Part 1) – 2016, (b) uniform, (c) fundamental mode shape and (d) triangular. It is found that under P-? effect, the initial lateral stiffness and base shear capacity get reduced for all the frames. The same can be correlated with the higher lateral displacement Thus, the absence of P-? effect causes overestimation of base shear capacity for the IMRF. The initial global stiffness predicted by the IS: 1893 (Part 1) – 2016 is the least among the lateral stiffness observed under all the load patterns. However, the uniform displacement profile provides the maximum base shear capacity of IMRF among all the load patterns.

Experimental Investigation of Exterior Reinforced Concrete Beam-Column Connections Subjected to Reversal Loading

Eight full-scale reinforced concrete beam-column subassemblages, 4 for each non-ductile and ductile detail, were tested under quasi-static cyclic loading. All test specimens were mainly designed for gravity service loads. Four specimens named as non-ductile connections were constructed with typical reinforcement details using in Thailand. The others were assembled with details described by the seismic design building code of Thailand, known as the 1301/1302-61 code. Their performance was examined in terms of lateral load resistance, ductility index, stiffness, energy dissipation, failure modes, including joint shear strength. The test results indicated that the specimens with ductile details achieved better seismic performance in every aspect, particularly specimens with adequate joint shear strength designed according to the SST method. The ductile details have no effect to retard the stiffness degradation in the elastic range, but helped to slow the rates of stiffness degradation after the specimens reached their peak loads. The transverse reinforcement in the joints was more efficient to enhance the ductility of joints with lower joint shear strengths (J1 and J2) than the sufficient joints (J3 and J4). Based on the SST method, the connections with low shear strength capacity, J1, J1D, J2, J2D, J3, and J4 suffered with severe joint shear failure (JS), although their beam sections reached the flexural moments. On the other hand, specimens with high joint shear strengths, J3D and J4D, experienced the beam failure (BF) with mild joint shear failure (JS). Test data also demonstrated that a specimen with lesser amount of joint reinforcement exhibited satisfactory seismic behavior, as long as the joint was provided with the adequate shear strength designed by the SST method. Finally, the ACI 318 Building Code overestimated the shear strength of exterior beam-column joints. Moreover, the simplified SST model much better predicted the demand joint shear strength than the ACI 318 Code.
 HIGHLIGHTS
 
 Numerous surveys of RC buildings after earthquakes also confirmed the inadequate detailing of beam-column joints such as presence of splices, lack of hoops, deficiency of beam bar anchorage, and no steel joint stirrups in the joint
 The ductile details have no effect to retard the stiffness degradation in the elastic range, but helped to slow the rates of stiffness degradation after the specimens reached their peak loads. The transverse reinforcement in the joints was more efficient to enhance the ductility of joints with lower joint shear strengths (J1 and J2) than the sufficient joints (J3 and J4)
 The ACI 318 Building Code overestimated the shear strength of exterior beam-column joints. Moreover, the simplified SST model much better predicted the demand joint shear strength than the ACI 318 Code
 Based on the SST method, the beam-column connections with low shear strength capacity, J1, J1D, J2, J2D, J3 and J4 suffered with severe joint shear failure (JS), although their beam sections reached the flexural moments. On the other hand, specimens with high joint shear strengths, J3D and J4D, experienced the beam failure (BF) with mild joint shear failure (JS)
 The deterioration of beam-column joints under seismic could be effectively restrained by the ductile details according to 1301/1302-61 code with adequate shear strength capacity determined by using the equation of SST model
 
 GRAPHICAL ABSTRACT

Modelling Studies of Retrofitted Anchorage System in Exterior Beam Column Joint by Supplementary Steel

A Nonlinear finite element based ABAQUS modeling studies were conducted to evaluate the performance of exterior Beam Column Joint (BCJ) under quasi-static test loads. Six integrated BCJ models representing different configurations of beam reinforcement anchored in joint are verified by using a novel retrofitting technique called "Post Installation of Supplementary Anchorage" (PISA) by using headed bar as supplementary steel. The configuration of beam reinforcement anchored in column are described by straight bar,90 degree bend ,180 degree hook (confirming to design code IS456:2000) and single head, double head bars (confirming to ACI 318-19, ACI 352R-02 ) and 90 degree long bend of ductile detailing (as per IS 13920-2016). Two series (A&B) of integrated joint specimens representing conventional (series-A) and retrofitted anchorage (series-B) systems are modeled and tested by using ABAQUS software. The test parameters considered are configuration of anchorage system and presence of supplementary anchorage. The test variables representing nonlinear performance of retrofitted joint system are Von Mises stress conditions, Principal tensile stress, Moment-Rotation, Degraded stiffness, Crack mechanics and Damage index. The results shows good improvement of post failure conditions of exterior beam-column joint such as relocation of plastic hinge mechanism and failure mechanics of retrofitted joint system. Also the results validated with experimental program on typical specimens casted and tested. This study imparts useful information on implicit retrofitting methods applied by external means in exterior beam-column joint. It also promotes performance based design principles with viable construction practice.

Diaphragm abutment Californian bridges subjected to UCERF2 rupture scenarios: Complete damage state evolution with improvements to seismic codes

The seismic design of bridges in California has evolved largely around 1970 to 1990 in terms of transverse reinforcement spacing and ductile detailing. This study focuses on diaphragm abutment bridges with design criteria ranging from pre-70's design to post 90's design in California and subjecting them to future possible earthquakes on California faults, according to the Uniform California Earthquake Rupture Forecast (UCERF). Using the synthetic ground motion from Southern California (Elysian Park, San Jacinto, and Southern San Andreas) and Northern California (Hayward, and Northern San Andreas) at DesignSafe data repository as base excitation, fragility analysis of diaphragm abutment bridges within Los Angeles, San Bernardino, and San Francisco regions is presented. The scenario with the highest threat to bridges in each of the 3 regions is highlighted. Furthermore, the result reveals the importance of the orientation of bridges on the median fragility for the complete damage limit state and compares them with HAZard US (HAZUS) fragility parameters.

A Literature Review on Seismic Response of Floating Column Building

Abstract: Floating column building is a new fascination for engineers. As floating column buildings provides more space and good aesthetics to the building. But have high structural challenges, when a floating column is provided in a multi-story building in a high seismic zone. This paper reviews several studies conducted on the floating column building and its behavior under seismic loads. This paper studies that floating column building are vulnerable to the high seismic zones. The risk of damage also depends on the shape and size of the buildings.The ductile detailing of the joints is the promising solution for immediate failure of such buildings. Keywords: Floating Column, Response spectrum analysis. Vulnerable, damage, multi-story

A novel damage index for reinforced concrete beam-column joint using acoustic emission technique

Acoustic Emission (AE) is a non-destructive Structural Health Monitoring (SHM) technique used to detect the presence and movement of defects in reinforced concrete structures. Various AE based techniques help to identify the occurrence of damage, but there is a need to develop a mechanism for the evaluation of damage index based on AE parameters. This study investigates the ability of AE energy parameters to detect damage to a reinforced concrete (RC) beam-column joint (BCJ). An experimental study has been conducted to test BCJ under cyclic load, and damage progression has been monitored using AE parameters. The results showed a significant increase in energy dissipated and AE energy when a BCJ is reinforced with ductile detailing. Further, a relationship has been developed between energy dissipated and AE energy to determine the damage index. A novel damage index based on AE energy has been developed for reinforced concrete beam-column joints.

Influence of composite floor slab on seismic performance of steel plate shear walls

Steel plate shear walls (SPSWs) consisting of unstiffened thin steel plates attached to the horizontal and vertical boundary steel elements are often used as the lateral force-resisting systems in buildings. The presence of composite floor slabs may not only alter the force demands on the boundary elements but also influence the failure mode of SPSW systems under seismic loading. This study addresses this research gap through experimental investigation of a single-story single-bay SPSW with floor slab subjected to constant gravity load and gradually increasing reversed cyclic lateral displacement. A ductile detailing of beam-column joint has been proposed as an alternative to the conventional reduced beam sections. The test specimen demonstrated a stable hysteretic response up to 5.5% story drift without significant reduction in the lateral strength. The proposed connection ensured the desired hinge mechanism and high ductility of the SPSW specimen. Additionally, numerical analysis of SPSW systems with and without composite slabs has been conducted to predict their load-resisting capacities and modes of failure under lateral loading. The presence of the floor slab increased the axial load demand on the vertical boundary element and the shear deformation demand on the horizontal boundary elements of the SPSW system.

An experimental study on R.C beam-column joints under cyclic loading

Studies on the performance of structures under cyclic loads have attained great significance in the recent past, in the context of increased structural damages during disasters like earthquakes. A closer observation of such damages with particular reference to R.C framed buildings reveals that beam-column junctions are very crucial in determining the performance of the total building structure subjected to cyclic loading. An experimental study is taken up in the present work to stimulate cyclic load on structural models of R.C beam-column junctions and investigate the influence of certain key parameters on their performance. Three commonly found field practices viz., Normal detailing at the junction, ductile detailing at the junctions and defective workmanship at the junction, are chosen for the study. IS 13,920 guidelines are adopted for ductile detailing while use of M−20 mix in place of supposed M30 grade to be used, is adopted as indicator of defective workmanship. Responses of the specimens were noted in terms of load-deflection behavior, first cracking, complete crushing, number of cycles taken for failure etc. From the results obtained, the performance of the specimens were noted in terms of load-deflection hysteresis loops, cracking pattern and behavior, stiffness degradation, ductility factor and energy absorption. It is observed that the specimens with good workmanship and ductile detailing are performing better under cyclic loads.

Cost optimization of RCC column using discrete optimisation method

Primarily, columns carry axial loads, and therefore, these are designed for compression. Other loads from snow, wind, or earthquake forces can cause bending in the columns. Columns then need to be developed for Axial Load and Bending. The cost-effective design of columns is the biggest problem when we are going to design a building. The optimal design of a building depends on the costs of all three reinforced concrete elements: beam, column, and slabs. These all should also be designed with optimal. This research work aims to find the minimum cost of RCC column subjected to two types of loadings i,e axial loading and uniaxial moments. The objective of this research work was to reduce the total price of RCC column after applying all the design guidelines according to BIS codes 456:2000 (without ductile detailing) and 13920;1993 (with ductile detailing). Generally, we cannot mark a structure with a minimum cost but it should also design according to the Indian standard codes. The cost comparison of RCC column results, taken according to BIS codes, has been carried out to check the differences in the price of both cases. We found that in the case of 4 m column length, the axial load, moment, and grade of steel values are 1200kN, 200kNm, and 500 N/mm2 respectively. The variation in cost is 11%-12% for all the phases of concrete. We also found that reinforcement detailing cost variation in 9 m and 12 m column lengths is significantly less. The cost percentage of optimal cost of RCC column is reduced when force and moment are increased. The Genetic Algorithm and Matlab software has been used in this research work.

Fire performance of earthquake-damaged reinforced concrete columns: an experimental study

PurposeEarthquake tremors not only increase the chances of fire ignition but also hinder the fire-fighting efforts due to the damage to the lifelines of a city. Most of the international codes have independent recommendations for structural safety against earthquake and fire. However, the possibility of a multi-hazard event, such as fire following an earthquake is seldom addressed.Design/methodology/approachThis paper presents an experimental study of Reinforced Concrete (RC) columns in post-earthquake fire (PEF) conditions. An experimental approach is proposed that allows the testing of a column instead of a full structural frame. This approach allows us to control the loading and boundary conditions individually and facilitates the testing under a variety of these conditions. Also, it allows the structure to be tested until failure. The role of parameters, such as earthquake intensity, axial load ratio and the ductile detailing of the column on the earthquake damage and subsequently the fire performance of the structure, is studied in this research. Six RC column specimens are tested under a sequence of quasi-static earthquake loading, followed by combined fire and axial compression loading conditions.FindingsThe experiment results indicate that ductile detailed columns subjected to 4% or less lateral drift did not lose significant load-carrying capacity in fire conditions. A lateral drift of 6% caused significant damage to the columns and reduced the load-carrying capacity in fire conditions. The level of the axial load acting on the column at the time of earthquake loading was found to have a very significant effect on the extent of damage and reduction in column load capacity in fire conditions. The columns that were not detailed for a ductile behavior observed a more significant reduction in axial load carrying capacity in fire conditions.Research limitations/implicationsThis study is limited to columns of 230 mm size due to the limitations of the test setup. The applicability of these findings to larger column sections needs to be verified by developing a numerical analysis methodology and simulating other post-earthquake-fire tests available in the literature.Originality/valueThe experimental procedure proposed in this paper offers an alternative to the testing of a complete structural frame system for PEF behavior. In addition to the ease of conducting the tests, the procedure also allows much better control over the heating, structural loading and boundary conditions.

Shear Wall and Frame Dual Systems Featuring Discontinuous Load Paths in Frame Elements in Low-to-Moderate Seismic Regions

ABSTRACT Reinforced concrete buildings constitute a significant portion of construction in Australia. Many existing buildings in Australia and other low to moderate seismic regions have been designed with little to no consideration for ductile detailing. The majority of these buildings also possess vertical irregularities, which can exacerbate their vulnerability in an earthquake event. The seismic performance of shear wall and frame dual systems possessing discontinuities in frame elements in the form of ductility and failure mechanism has been assessed. And design recommendations in terms of response modification factors and designation of appropriate methods of analysis have been provided.

Reinforced concrete beam-column joint’s ductility behavior

A beam column junction is a key zone in a reinforced concrete moment resistant frame. It is exposed to a huge deal of stress throughout severe ground motion, and its performance has a noteworthy impact on the structure’s reaction if the ductility is inadequate, resulting in serious structural collapse. Use IS code 13920:1993 and provide ductile reinforcement according to ductile detailing of reinforcement beam column junction and ductile detailing of reinforcement beam column junction to improve the ductility of conventional beam column joints. The dimensions of the beam column junction are 700 mm*700 mm with a c/s of 200 mm*100 mm. The specimen will be cast in concrete to M30 specifications.