Progressive Collapse Study of Seismically Designed Low Rise Reinforced Concrete Framed Structure

Two-dimensional reinforced concrete frames with the storey of different heights are simulated to the column removal scenario to understand the progressive collapse behaviour by using General Services Administration (GSA 2003) guidelines. Numerical modelling of 4-, 8- and 12-storey structures with different analyses procedures were evaluated such as Linear Static Analysis (LSA), Linear Dynamic Analysis (LDA) and Nonlinear Static Analysis (NLSA) using ETABS 2015. The liner results demonstrate the corner column removal and thus make the structure more vulnerable to progressive collapse when compared to the middle column removal and nonlinear results indicate that the progressive collapse of the structures decreases with increasing the height of the storey.

Interior brick-infill partitions are usually considered as\nnon-structural components and only their weight is accounted for in\npractical structural design. In this study, their effect on the progressive\ncollapse resistance of an RC building subjected to sudden column loss\nis investigated. Three notional column loss conditions with four\ndifferent brick-infill locations are considered. Column-loss response\nanalyses of the RC building with and without brick infills are carried\nout. Analysis results indicate that the collapse resistance is only\nslightly influenced by the brick infills due to their brittle failure\ncharacteristic. Even so, they may help to reduce the inelastic\ndisplacement response under column loss. For practical engineering, it\nis reasonably conservative to only consider the weight of brick-infill\npartitions in the structural analysis.

In the past few decades, effect of natural hazards such as earthquake, wind etc. on existing structures has attracted the attention of designers. Progressive collapse is nothing but a condition of indigenous failure of prime structural element which in turn leads to the collapse of connecting members and then it leads to the additional collapse. For the case of progressive collapse, damage is included in the model through the elimination of important structural component like column. The progressive collapse design guidelines primarily suggest the simplified analysis actions occurred due to the sudden removal of specific columns in a building. The study of analytical approaches for evaluating progressive collapse is carried out by linear static analysis using Alternate Path Method (APM) recommended in General Service Administration (GSA) guidelines and the same is presented in this study. This study involves the use of various general methods of progressive collapse design & evaluation based on numerical mock up and experimental information. For this study, a multistoried composite building (i.e. G+7) is considered. The prime objective of this study is to analyze the composite building by removing columns at different locations and finding out critical location of column vulnerable to progressive collapse and also prevention of progressive collapse of structure using linear static analysis. Location of removed column, Number of floors, vertical irregularity were studied and their influence was also carried out in this research.

In this study, the framework of performance-based earthquake engineering is used to predict the seismic collapse risk of California's older (non-ductile) and modern (ductile) reinforced concrete frame structures. Collapse performance assessments are conducted for two sets of structures, those designed according to an out-dated building code, the 1967 Uniform Building Code (UBC), and those designed according to modern building code provisions, the 2003 International Building Code (IBC). Each set includes 2, 4, 8 and 12 story reinforced concrete frame buildings, designed as space and perimeter frame systems. These preliminary results provide measures of collapse safety of reinforced concrete frame structures and are used to evaluate the level of safety provided by modern building codes, and to quantify differences in safety between older and moden structures, answering questions such as "how safe are code-conforming reinforced concrete frame structures?" and "how much more likely are existing reinforced concrete frames to collapse in an earthquake?"

Investigation of progressive collapse resistance and inelastic response for an earthquake-resistant RC building subjected to column failure

The effectiveness and the sensitivity of a Wireless impedance/Admittance Monitoring System (WiAMS) for the prompt damage diagnosis of two single-storey single-span Reinforced Concrete (RC) frames under cyclic loading is experimentally investigated. The geometrical and the reinforcement characteristics of the RC structural members of the frames represent typical old RC frame structure without consideration of seismic design criteria. The columns of the frames are vulnerable to shear failure under lateral load due to their low height-to-depth ratio and insufficient transverse reinforcement. The proposed Structural Health Monitoring (SHM) system comprises of specially manufactured autonomous portable devices that acquire the in-situ voltage frequency responses of a network of twenty piezoelectric transducers mounted to the RC frames. Measurements of external and internal small-sized piezoelectric patches are utilized for damage localization and assessment at various and increased damage levels as the magnitude of the imposed lateral cycle deformations increases. A bare RC frame and a strengthened one using a pair of steel crossed tension-ties (X-bracing) have been tested in order to check the sensitivity of the developed WiAMS in different structural conditions since crack propagation, damage locations and failure mode of the examined frames vary. Indeed, the imposed loading caused brittle shear failure to the column of the bare frame and the formation of plastic hinges at the beam ends of the X-braced frame. Test results highlighted the ability of the proposed SHM to identify incipient damages due to concrete cracking and steel yielding since promising early indication of the forthcoming critical failures before any visible sign has been obtained.

Seismic performance evaluation of novel RC frame structure with kinked rebar beams and post-yield hardening columns through shaking table tests

The Progressive collapse is a local failure which may cause the building to be severely damaged or entirely collapsed. Both US General Service Administration (GSA) and Unified Facility Criteria (UFC) have produced two different criteria to design new buildings and to check the safety of the existing structures against progressive collapse. The main objective of this article is to compare the results obtained by both linear static and nonlinear dynamic analysis methods suggested by GSA of a building originally designed according to the Egyptian Code of Practice, and to investigate the effect of adding bracing members in the first story to prevent the successive failure mode. The building has three bays in X-direction and two bays in Y-direction with seven stories. It was concluded that designing frames to sustain earthquakes, as well as adding bracing members in the perimeter of the first floor will enhance the structure behavior against progressive failure mode

The influence of masonry infill walls on the progressive collapse performance of reinforced concrete (RC) frame structures was investigated in this paper, using a nonlinear dynamic analysis approach. Based on ANSYS/LS-DYNA finite element software, two finite element models of RC frame structures with and without masonry infilled walls were established. Then, the collapse modes of the two RC frame structure models were analyzed for different scaled distance blast loads, different locations of column damage, and different span numbers. The results show that with the increase of explosive amount, the collapse degree of the structure is more serious in the same time. Under the condition of destroying the outermost central column, the degree of progressive collapse of the RC frame model with infilled walls in the same time is lower than that of the RC frame model without infilled walls. The RC frame model with infilled walls is more resistant to collapse when the outermost side columns are damaged. With the increase of span number, the structure is more likely to be damaged and collapsed.

Progressive collapse occurs when key members of a supporting structure are separated due to accidents or terrorist attacks, causing the remaining structural elements to fail. This study conducted linear and non-linear static analysis on a reinforced concrete frame structure to determine its ability to prevent growth and save lives in an accident. The results showed weak connections and failure modes as load strength increased. The model was found to be safe according to GSA guidelines and could withstand explosions, making the stone more affordable and saving lives. Improvements in the design of the long beam and plastic hinges could further enhance safety.. Keywords: Pushover, accidental avoid, Demand Capacity Ratio, Wrechking pushover, concrete

The growing need for blast-resistant designs in structural engineering is driven by the rising threat of terrorism, accidental explosions, and the significant risk of progressive collapse. This study presents a numerical procedure for analyzing the progressive collapse of Reinforced Concrete (RC) framed structures due to blast loads, addressing the gap in current methodologies. Traditional approaches such as the Alternate Load Path method, which are code-based and threat-independent, mainly focus on sudden column loss scenarios but do not fully capture the dynamic nature of blast-induced, threat-dependent collapses. Hence this study addresses the need for a computationally efficient and reliable method to predict and model progressive collapse under blast loading. This study employs a comprehensive numerical investigation using Finite Element Method where a seven-storeyed RC building is assessed for progressive collapse under blast loading. Progressive collapse analysis was executed using a commercially available Finite Element Analysis software, adhering to the Linear Static Procedure specified in the General Services Administration (GSA) guidelines, while blast load scenarios were examined through a nonlinear direct integration time history analysis. Different blast parameters, including charge weight and standoff distances, are varied to evaluate their impact on the structural integrity of the building. The study differentiates between threat-independent analysis, considering four column removal locations, and threat-dependent (blast-induced) scenarios with three distinct column removal positions. The scope of this study delves only into the perimeter blast scenarios neglecting the internal explosions. Demand Capacity Ratios (DCR) of columns were calculated to determine the susceptibility of the building to progressive collapse, with a DCR greater than 1 indicating failure. The numerical model was validated against the GSA baseline model. In threat-independent analysis, 30%, 60%, 22%, and 44% of the considered columns under corner, long side, short side, and interior column removal scenarios respectively exceeded the acceptable DCR criteria. In threat-dependent analysis, 100% of the considered columns under each blast induced column removal scenario exceeded the acceptable DCR criteria. This emphasizes the need for scenario-based planning in structural design to reduce collapse risks. The identification of critical columns, for threat-independent analysis as those directly above the removed column and on the topmost floor and for threat-dependent analysis as ground floor columns adjacent to the removed column, reveals potential weak points for progressive collapse initiation. The analysis of blast-induced progressive collapse reveals significantly higher DCR values than threat-independent assessments. Even the minimum percentage increases of DCRs when transitioning from threat-independent to threat-dependent analysis reaches high values up to 995%, 325%, and 981% for corner, long side, and short side column removal scenarios respectively. This specifies the importance of integrating blast resistance into the structural design of high-risk buildings. As a result, this study contributes to the understanding of structural dynamics under blast loads and offers a framework for the analysis of progressive collapse in RC buildings.

Design Methods of Reinforce-concrete Frame Structure to Resist Progressive Collapse in Civil Engineering

Advantages of EPS module Reinforced concrete frame structure are enormous. For example, High precision, low cost, fast construction speed, low energy consumption. It has a wide application prospect in town building and post disaster reconstruction, cold region housing industrialization and other fields. It must have considerable economic benefit, if we can optimize the design reasonable on EPS module Reinforced concrete frame structure. As the design variables, constraint conditions, calculation and other reasons. In fact we are not on the EPS module Reinforced concrete frame structure to optimize the design of effective. This paper analyzed the EPS module of reinforced concrete frame structure and engineering optimization design theory development trend, research on EPS module of reinforced concrete frame structure optimization design problem and discusses the EPS module structure of reinforced concrete frame structure optimization design of the feasibility of using genetic algorithm.

Design of safe structures with resistance to progressive collapse is of paramount importance in structural engineering. In this paper, an efficient optimization technique is used for optimal design of steel moment frames subjected to progressive collapse. Seismic design specifications of AISC-LRFD code together with progressive collapse provisions of UFC are considered as the optimization constraints. Linear static, nonlinear static and nonlinear dynamic analysis procedures of alternate path method of UFC are considered in design process. Three design examples are solved and the results are discussed. Results show that frames, which are designed solely considering the AISC-LRFD limitations, cannot resist progressive collapse, in terms of UFC requirements. Moreover, although the linear static analysis procedure needs the least computational cost with compared to the other two procedures, is the most conservative one and results in heaviest frame designs against progressive collapse. By comparing the results of this work with those reported in literature, it is also shown that the optimization technique used in this paper significantly reduces the required computational effort for design. In addition, the effect of the use of connections with high plastic rotational capacity is investigated, whose results show that lighter designs with resistance to progressive collapse can be obtained by using Side Plate connections in steel frames.

The design of new buildings using Progressive Collapse criteria has become better understood since the nation's largest landlord, the General Services Administration (GSA), incorporated progressive collapse design criteria into their standard design requirements. Other institutions, such as the Department of Defense (DoD), also have incorporated progressive collapse design criteria into their design requirements for both new and existing structures. The DoD presents their progressive collapse requirements in the Unified Facilities Criteria (UFC) document UFC 4-023-03 (25 January 2005), Design of Buildings to Resist Progressive Collapse. While there are numerous similarities between the UFC progressive collapse criteria and the GSA Progressive Collapse Guidelines, there are several key differences which can increase the time and cost of the design process, as well as the final construction cost of the project.