Inter-story Drift Research Articles

Cyclic Behavior of the Column-Tree Moment Connection with Weakened Plates: A Numerical Approach

The use of column-tree connections is common in controlled shop environments due to their cost-effectiveness in achieving ductile welds. Field bolts are also easy to install and inspect. However, there is currently no prequalification available for these connections, their performance is not fully understood, and the cost of aftermath repairs is still a major concern for owners. In this research, analytical and numerical studies were performed to assess the cyclic behavior considering the effects of the bolted splice location, bolt slippage, and splice plate thickness. Fourteen numerical models using the finite element method in ANSYS software were analyzed to evaluate the nonlinear behavior of moment connection configurations in terms of the strength, stiffness, ductility, energy dissipation, and overall cyclic response. The results showed that appropriately proportioned bolted splice connections can meet the requirements for prequalified moment connections. The models complied with the criteria established in AISC 358 and achieved flexural resistance that was higher than 80% of the beam plastic moment at 4% of the interstory drift ratio. The weakened plates concentrated the inelastic action, which allowed us to prevent the brittle behavior and damage to the column, welding, and other components of the moment connection. Complex geometries or specially fabricated parts were not required, providing a cost-effective way to control seismic-related damage. Also, required repairs are based on the replacement of standard parts, reducing operational detentions in facilities. Finally, the moment connection studied is classified as partially restrained (PR) according to the requirements established in AISC 360.

Nonlinear time-history analysis of the Evolution Tower resting on cellular raft due to earthquake loads

This study includes an investigation of using a cellular raft over piles on the seismic response of both a twisting and regular tower using the direct method, demonstrating the variance between a solid raft and a cellular raft. Both towers are 52 stories high and made of reinforced concrete. They were also built on a reinforced concrete piled-raft foundation. The soil model is thought to be multi-layered and has the same profile as the zone under investigation (New Mansoura, Egypt). All structural properties (dimensions, section properties, materials) are equal to allow a fair comparison of output response for both towers. The sole difference between the two towers is their elevation. The study is carried out under seismic loads using nonlinear time-history analysis. All analyses are carried out employing finite-element software (Midas GTS NX). Thus, seven distinct earthquake records with full 3D models were used for time-history research. According to the findings and discussions, it is concluded that adopting a cellular raft can reduce the dynamic response of the towers. Considering the soil–structure interaction, the maximum inter-story drift ratio decreases by 8.17% for the twisting tower and 5.58% for the regular tower while using the cellular raft. Furthermore, the regular tower is more effective than the twisting tower at resisting lateral loads.

Hysteretic and seismic performance of disc spring-based self-centering viscous dampers for improved seismic resilience

This study presents an innovative self-centering viscous damper with flag-shaped hysteretic behavior to address critical issues in the current self-centering bracing system and enhance its structural resilience against earthquakes. First, the basic configuration, working principle, and simplified physical model are described in detail. Then a comprehensive experimental study is conducted on large-scale damper specimens with different design parameters. The damper exhibits a typical flag-shaped hysteretic behavior, and disc springs combined in parallel can significantly increase the load-bearing capacity and the second stiffness of the damper. Subsequently, a numerical modeling technique is developed to capture the complex nonlinear behavior of the proposed damper accurately. Finally, the study is further extended to a structure-level analysis to investigate the influence of key brace-design parameters on the overall response of the structure along with its collapse fragility. It is found that the rational design of the self-centering viscous damper can effectively suppress the peak inter-story drift, residual inter-story drift, and peak absolute floor acceleration of the structure, thereby achieving a favorable trade-off in the design outcome. Additionally, reducing the self-centering ratio and increasing the loading stiffness ratio are effective measures to improve the collapse resistance of such structures.

Experimental investigation using demountable steel-concrete composite reduced web section (RWS) connections under cyclic loads

This paper presents an experimental study of demountable steel-concrete composite reduced web section (RWS) connections for use in seismic areas. Four composite connection specimens were subjected to sagging and hogging moments to investigate the performance of RWS connections under reversible actions. For such purpose, a single web opening was created near the beam-column joint. Focus was made on the effects of perforation location and composite beam-slab action induced by bolted shear studs within the protected zone. Results indicate that employing RWS connections for seismic retrofit is a viable solution capable of achieving a performance similar to that observed for RBS connections in new buildings. Notably, a Vierendeel Mechanism is formed, allowing for plasticity development in the beam. All RWS connections were capable of achieving an interstory drift larger than 4%, thereby complying with the performance targets set by ANSI/AISC 358-16, ANSI/AISC 341-16 and EC8. Moreover, the deformation of beam-slab shear-transfer bolts was small enough to allow for disassembly after the tests, indicating that the proposed solution could enable reuse and post-earthquake retrofitting.

Macro-modelling method for the in-plane behaviour of the damped masonry infill wall in a frame structure

The damped masonry infill wall (DMIW) has been experimentally validated to have the ability to ameliorate the seismic problem caused by the diagonal action of the traditional masonry infill wall (TMIW). To lay the foundation for further structural analysis, a macro-modelling method for predicting the in-plane behaviour of the DMIW is developed. In this paper, the in-plane working mechanism is illustrated first and then a macro model of two diagonal elements which represent the behaviour of the damping layer joints (DLJs) is developed. In addition, the modelling method of the DLJ is developed and the method of identifying the parameters is considered. At last, experimental results are used to verify the macro-modelling method of the DMIW, followed by a case study on the seismic performance evaluation of the frame infilled by the DMIWs. The results indicate that the macro-modelling method has a clear physical meaning and is capable of predicting the in-plane cyclic behaviour of DMIW. The storey drifts and shear response of the frame infilled by the DMIW under the earthquake are almost the same as that of the bare frame, indicating that the effect of the DMIW on the bare frame is much less than that of the TMIW and further confirming that the DMIW is able to ameliorate the seismic problems caused by the diagonal action of the TMIW. In addition, the inter-storey drift is evenly distributed without a significant increase in the case where the DMIWs are not placed only in a particular storey, suggesting that the risk of developing the soft-storey failure mechanism of the frame can be significantly reduced even in the case where the arrangement of the TMIWs is irregular along the height.

Experimental study on seismic performance of timber frame with novel energy-dissipation joints

The beam-column joints of traditional timber frames are mortise-tenon or iron hook joints, which are prone to joint damage during earthquakes, thus causing the collapse of buildings. To avoid such adverse seismic damage, this study proposes an energy-dissipation joint applied to timber frames. The energy-dissipation joints serve both as joint connections and knee braces, providing multiple lines of seismic defense. To verify the effectiveness of the energy-dissipation joints, quasi-static tests were conducted on four specimens. It is shown that the energy-dissipation joints successfully achieve the intended objective. When the inter-story drift ratio of the timber frame is small, the energy-dissipation elements in the energy-dissipation joints remain in an elastic state. As the inter-story drift ratio increases, the energy-dissipation elements in the energy-dissipation device gradually begin to yield and dissipate energy. The energy-dissipation elements cease operation when the inter-story drift ratio is relatively large, and the energy-dissipation device transforms into knee brace to provide lateral stiffness to the timber frame. Compared with the traditional timber frame, the load-bearing capacity, lateral stiffness, and energy dissipation capacity of the timber frame with the energy-dissipation joints were significantly improved, and the failure mode shifted from beam-column joint damage to timber column fracture damage, and no collapse occurred under an inter-story drift ratio of 12.86%.

Seismic response of two-storey steel frame equipped with metallic yielding and viscous dampers under far- and near-field earthquakes: Shaking table tests and numerical investigations

Seismic energy dissipation technology is widely used in building structures to mitigate earthquake damage; two typical energy dissipation devices (EDDs), viscous fluid dampers (VFDs) and metallic yield dampers (MYDs), are often used. To investigate the effects of different types of EDDs on seismic performance, shaking table tests were conducted on a two-storey moment-resistance steel frame (MRSF). This study examined three types of damping schemes: VFDs only, MYDs only, and a combination of both. The test results showed that different damping schemes had different effective stiffnesses and damping ratios. The basic frequency and damping ratio of the MRSF with hybrid dampers increased by 36.18% and 38.41%, respectively, compared with those with VFDs only. Compared with the other two controlled MRSFs using a single type of EDDs, the MRSF equipped with hybrid dampers can effectively coordinate the control of interstorey drifts. To further analyse the impact of pulse-type ground motions (GMs) on the dynamic responses of the controlled MRSFs, numerical models were established for all test models, and the nonlinear time-history analysis (NTHA) was performed. The numerical results fitted well with the test results and showed that the hybrid damping scheme can take full advantage of the two types of EDDs. The mean dissipation energy ratio of the dampers was 86% with GMs with an intensity of 0.80 g. There was a significant difference in the seismic damping effect of the controlled MRSFs with different types of seismic excitations. The acceleration control effect of the MRSF with only MYDs was best with near-field pulse-type GMs, with up to a 30% reduction over the MRSF with only VFDs. The acceleration control effect of the hybrid-controlled MRSF was best with near-field non-pulse GMs; the 1st-storey acceleration control of the hybrid damping MRSF was reduced by up to 42.4% compared to the VFD. The displacement reduction rates of the three controlled MRSFs subjected to pulse-type seismic excitation were lower than those of the three MRSFs subjected to non-pulse-type seismic excitations.

Seismic response and performance prediction of steel buckling-restrained braced frames using machine-learning methods

Nowadays, Buckling-Restrained Brace Frames (BRBFs) have been used as lateral force-resisting systems for low-, to mid-rise buildings. Residual Interstory Drift (RID) of BRBFs plays a key role in deciding to retrofit buildings after seismic excitation; however, existing formulas have limitations and cannot effectively help civil engineers, e.g., FEMA P-58, which is a conservative estimation method. Therefore, there is a need to provide a comprehensive tool for estimating seismic responses of Interstory Drift (ID) and RID with novel approaches to fulfill the shortcomings of existing formulas. The Machine Learning (ML) method is an interdisciplinary approach that makes it possible to solve these types of engineering problems. Therefore, the current study proposes ML algorithms to provide a prediction model for determining the seismic response, seismic performance curve, and seismic failure probability curve of BRBFs. To train ML-based prediction models, Nonlinear Time-History Analysis (NTHA) and Incremental Dynamic Analysis (IDA) were performed on the 2-, to 12-Story BRBFs subjected to 78 far-field ground motions, and 606944 data points were prepared for different prediction purposes. The results indicate that the considered approaches are justified. For instance, the proposed ML methods have the ability to predict the maximum ID, maximum RID and maximum roof ID with the accuracy of even 98.7%, 95.2%, and 93.8%, respectively, for the 4-Story BRBF. Moreover, a general preliminary estimation tool is introduced to provide predictions based on the input parameters considered in the study.

Test study on performance of U80 standardized glass curtain wall system

In order to study the air infiltration performance, water penetration performance, structural performance under wind pressure and seismic inter-story drift performance of U80 standardized glass curtain wall system, one full size test specimen was designed according to the actual engineering situation. The test specimen was composed of six-unit curtain walls with exposed frames and six-unit curtain walls with concealed frames. According to the specification of United Stated, the various performance of the test specimen was investigated. The results show that the rate of air leakage of the specimen is within allowable values under design pressure. No water leakage is observed when the water penetration tests with static and dynamic pressure tests. During the structural performance tests at 100% design wind pressure, the deflections of framing members as well as glass panels are all within the allowable deflection limits. No breakage is observed under the 150% design wind pressure. Permanent deformations of framing members remain less than 0.1% of clear span. After 3 cycles of elastic and inelastic inter-story drift performance tests, no damage is observed. The U80 standardized glass curtain wall system has great air infiltration performance, water penetration performance, structural performance and seismic inter-story drift performance. And it can be used in the practical engineering.

Seismic response analysis of frame structures with uneven settlement of foundation considering soil-structure interaction

Uneven settlement of foundation (USF) has a significant effect on the seismic response of rigid foundation structures. However, the main reason for USF is that the balance between superstructure and site soil is failure. For investigating seismic response characteristics of the USF structure considering soil-structure interaction (SSI), USF closer to reality is achieved by nonlinear direct integration method and Stage-Construction method. And the model reliability is verified by Sway-Rocking model and Lagrange energy method. Five different models, three seismic intensities, and different values of USF are performed. The natural period, inter-story drift ratios, the plastic hinges rate, and torsional angles are extracted to investigate structural seismic response. The results show that the effect of SSI on the magnitude of increase in structural inter-story drift ratio is not monotonous with the increase of USF in the presence of earthquakes. The USF structure considering SSI may significantly affect its seismic response, and will suffer more structural damage compared to the rigid foundation and the even settlement foundation. The rigid foundation structure with large value of USF leads to severe stretching on the settlement area and increases damage to the structure. Finally, the USF structures have relatively large torsional angles at the top story, and will exhibit significant torsional behavior. Hence, it is necessary and reasonable to consider SSI in the seismic design of USF structures. The research results can provide some references for seismic design.

Response- and probability-based evaluation of spectrally matched ground motion selection strategies for bi-directional dynamic analysis of low- to mid-rise RC buildings

In this study, the effect of different strategies which consider various levels of constraints for spectrally matched ground motion (GM) selection on seismic responses of the buildings was evaluated. For this, six different three-dimensional buildings and three different local soil classes were considered. Various GM record sets were used for each strategy and local soil class pair to perform bi-directional nonlinear dynamic analyses of the buildings and maximum global and maximum inter-story drift ratio demands were obtained. To evaluate the efficiency of proposed strategies, the mean and dispersion of the demands were investigated. Then, the differences among the means of the seismic demands obtained for the strategies were evaluated using the analysis of variance method. Moreover, probability curves of the demands were constructed and compared. The results indicate that i) the mean of the demands generally used for code-based performance assessment can be estimated more consistently by the proposed strategies; ii) the supplemental constraints about spectral matching allow to control the dispersion of the spectral acceleration values of selected GMs and hence the dispersion of the demands; iii) using the appropriate one of the proposed strategies, GMs with desired dispersion of spectral accelerations can be acquired for probability-based performance assessment.

Design procedure and seismic performance assessment of structures equipped with bar-fuse dampers

The application of metallic yielding dampers (MYDs) to enhance the seismic performance of a structure has been a focus of attention in recent years. One recently introduced MYD is the bar-fuse damper (BFD). Its advantages include ease of installation, simple construction method, cost effectiveness (including replacement and repair costs) and shorter required repair time after strong seismic events. However, the most important benefits of the BFD are its high energy dissipation capacity, which can improve collapse safety and enhance the seismic performance of a structure. Despites its benefits, BFDs have been less studied than other types of MYDs. The present research provides a simple and efficient method for designing structures equipped with BFDs. Moreover, the mechanical characteristics of differently shaped BFDs made with different types of steel has been investigated using finite element analysis. Finally, the seismic performance of three model structures was evaluated using nonlinear time-history analysis. The results indicate that structures equipped with BFDs experience less inter-story drift and are less likely to undergo severe damage compared to similar bare moment-frame buildings.

The effect of an improved passive bumper on the seismic response of the base-isolated structure: Numerical simulations and optimization design

In this paper, a passive bumper, called Flexible Limit Protective Device (FLPD) which was proposed by the author before, was improved to better control the seismic response of the base-isolated structure when the isolation layer exceeds its limit deformation. To distinguish from the FLPD, the improved FLPD is called a Flexible Energy Dissipating Device (FEDD), and the FEDD has stronger dissipation capacity than the FLPD. Above all, the compression behavior of FEDDs is experimentally investigated and the experiment data of FEDDs are compared to that of FLPDs. Subsequently, the nonlinear model of FEDDs is obtained and verified using the experimental data. This obtained model was used to study the effect on the seismic response of the base-isolated structure (multi-degree-of-freedom system), namely isolator displacement and inter-story drift angle. An elite non-dominated sorting algorithm method (NSGA-II) is applied to optimize the design of FEDDs, the gap between isolators and FEDDs and stiffness of FEDDs. Finally, the seismic response of base-isolated buildings equipped with FEDD with optimal parameters is numerically simulated. The results show that FEDDs with optimal parameters can effectively reduce the isolator displacements, and keep the inter-story drift angle within the safe range when the isolation layer exceeds its limit deformation during earthquakes.

Seismic reinforcement analysis and measurement research of reinforced concrete frame structure

In China, there are many reinforced concrete frame buildings that have reached the end of their design life, or have not been designed with seismic requirements in mind and need to be reinforced. In this paper, a reinforced concrete frame structure which needs to be reinforced is taken as an example. Two common reinforcement methods are used to reinforce the reinforced concrete frame structure by adding shear wall and increasing column section. BIM-GSSAP software is used to analyze maximum inter-storey drift angle and the member response under frequent earthquakes, and the whole structure of the weak layer under rare earthquakes is checked. The results show that both methods can significantly improve the seismic performance of buildings. At the same time, combined with the project example, the advantages and disadvantages of the construction process are analyzed, which can provide a useful case reference for this kind of reinforced concrete frame structure projects.

Seismic behaviour of post-earthquake composite frame structures with different damage levels

Since earthquakes pose a huge threat to buildings, the post-earthquake safety assessment is quite important, especially in earthquake-prone areas. This paper investigates the seismic performance of post-earthquake composite frame structures with different damage levels. Two-stage nonlinear time history analysis is carried out for a ten-story steel–concrete composite frame and the peak ground acceleration (PGA) of the seismic waves is used as the main parameter characterizing the seismic intensity and damage level. In the first stage, the seismic waves with the PGAs of 0.20 g, 0.30 g and 0.40 g are applied to the frame to result in three different damage levels. The peak inter-story drift ratios, residual inter-story drift ratios and plastic hinge ratios of the structure in the first-stage earthquakes are analysed, which presents a uniform distribution pattern for the three damage levels. The composite frame is evaluated as structurally safe at all three damage levels based on the limits of residual inter-story drift ratios given in current standards. In the second stage, the seismic waves with the PGA of 0.40 g are used to explore the residual capacity of the structure subjected to strong earthquakes. The dynamic responses of the intact structure and the structure with different damage levels are compared. The results indicate that despite the recognised structural safety, pre-existing seismic damage can enlarge the lateral deformation, reduce the internal forces and resistance capacity and increase the plastic hinges when the composite frame is exposed to the second-stage earthquakes. Generally, the damage caused by earthquakes with the PGA of 0.40 g will have an obvious influence on the seismic behaviour of the post-earthquake structure, in which situation further safety assessment and structural repairs are necessary.

Comparison on seismic resilience of hybrid, isolation, and damping control reinforced concrete frame-shear wall buildings

To investigate the effectiveness of different vibration control methods in realizing seismic resilience of reinforced concrete (RC) frame-shear wall structures, four cases with different control methods were designed, including the damping control building using energy dissipation cladding panels (EDCPs) (RCFSW7-D), isolated building (RCFSW7-I), isolated building with enhanced stiffness of superstructure (RCFSW7.5-I), and hybrid control building using both EDCPs and isolation (RCFSW7-H). The critical seismic responses and resilient performance of four cases were analyzed based on the Chinese code. Maximum inter-story drift ratios (MIDRs) of RCFSW7-I, RCFSW7.5-I, and RCFSW7-H under maximum considered earthquake were 36%, 51%, and 72% lower than that of RCFSW7-D, respectively. Although the stiffness of superstructure of RCFSW7.5-I and RCFSW7-H were approximately identical, the MIDR of RCFSW7-H was 44% smaller than that of RCFSW7.5-I. Meanwhile, the maximum absolute floor accelerations (MAFAs) of three isolated structure under MCE were approximately 70% lower than that of RCFSW7-D. The seismic resilience level of RCFSW7-D was Level 1, which is dominated by the damage of structural components (SCs) controlled by MIDR and acceleration-sensitive non-structural components (ASNSCs) controlled by MAFA. The seismic resilience levels of RCFSW7-I and RCFSW7.5-I successfully increased to Level 2, leading by the effectively control of MAFA and damage of ASNSCs. However, the MIDR was not sufficiently controlled even the stiffness of superstructure was increased. In contrast, hybrid control building significantly reduced both the MIDR and MAFA through the currently utilization of seismic isolation and EDCPs, especially the MIDR and damage of SCs, leading to a seismic resilience level of Level 3.

Test of a full-scale two-story steel X-BRBF: Strong-axis instability of buckling restrained brace associated with out-of-plane bending of gusset connections

This paper presents tests and finite element analyses of a two-story, buckling-restrained braced frame (BRBF) with X-bracing configuration, called X-BRBF. The BRB used in this work is composed of a core plate sandwiched by a pair of the restraining member with bolts, called a sandwiched buckling restrained brace (SBRB). The weak-axis of the SBRB core that had a rectangular plate was positioned transverse to the dual-gusset plate connection and in-plane movement of the frame. The objectives of the frame test were to evaluate: (1) the seismic performance of SBRBs with a small width-to-thickness ratio of the core plate (i.e. 3), (2) the effects of free-edge stiffeners on the gusset and BRB stability, and (3) the BRB stability associated with the lateral torsional buckling (LTB) of the beam. The two-story X-BRBF subassembly had two test phases: all gusset connections had free-edge stiffeners in Phase 1 test, and freeedge stiffeners were removed from half of gusset connections in Phase 2 test. The X-BRBF in Phase 1 test exhibited good performance up to a second-floor drift of 1.6%, but in Phase 2 test the second-floor SBRB caused by LTB of the beam showed asymmetric instability about its strong-axis of the core plate at 1.6% second-floor drift. The other SBRB with no LTB of the beam showed one-side instability about its strongaxis at 2% second-floor drift (about 2.5% interstory drift). However, the strength degradation of the X-BRBF subassembly was not observed in the strong-axis instability of SBRBs, indicating an acceptable orientation of BRBs for eliminating a typical weak-axis buckling of BRBs together with out-of-plane bending of gusset plates. The strong-axis instability of SBRBs could be evaluated by using the BRB stability concept together with the measured out-of-plane deformation of gusset plates in Phase 2 test.

Numerical and experimental analysis in seismic performance of post-earthquake reinforced concrete frame retrofitted with ECC

In order to further demonstrate the effectiveness of engineered cementitious composites (ECC) in repairing and strengthening the post-earthquake damaged structure, at the overall structural level, experimental and numerical comparative analysis of structural seismic performance before and after “retrofitted with ECC” is conducted in this paper. A 1:2-scale reinforced concrete frame is tested under cyclic reversed loading and a new ECC material’s constitutive model is proposed in this paper for improving the accuracy and feasibility of numerical modelling. The modelling method and newly proposed constitutive model of ECC has been demonstrated to be workable and accurate. Based on numerical and experimental data, the increase of the average yielding displacement after the installation of ECC is relatively significant (80.4% to 156.4%), and the repairing method using ECC in post-earthquake damaged RC frame can restore and even exceed the original frame’s load bearing capacity. Comparing the ultimate inter-story drift ratio, the ratio with ECC is about 31.0% higher, indicating that ECC has good deformation capacity and the usage of ECC is indeed an effective method to improve deformation capacity in repairing and strengthening post-earthquake damaged structures. The results confirm the effectiveness and superiority of retrofitting ECC in post-earthquake damaged structures for the reason that the repaired structure can reach the same level of seismic performance as the original structure. The “repairable” characteristic can be used in the design of earthquake resilient structures.

Seismic retrofit of low-rise structures using rotational viscoelastic dampers

In this research, the efficiency of a rotational viscoelastic seismic energy dissipation device is evaluated in a theoretical framework. Unlike conventional dampers which block the bays, the main advantage of this damper lies within its vertical installation scheme that provides open space in the bay and architectural flexibility. The proposed damper consists of a steel column with viscoelastic hinges at both ends that dissipate the seismic energy. Conventional viscoelastic dampers usually act under translational deformation, whereas it acts under rotational deformations in the considered scheme. The theoretical foundation is laid for the proposed damper and is verified by comparing the results with the analytical model of the damper. The developed device is proven to be versatile in terms of stiffness and energy dissipation which can be easily adjusted. The application and efficiency of this damper is validated by retrofitting a soft-first-story structure to fulfill the enhanced performance objective. The performance of the structure under a suite of earthquakes is compared before and after the seismic retrofit in terms of maximum interstory drift ratio and residual displacement.

Seismic response of a steel frame considering the underground subway-soft soil-steel frame interaction

The existence of the underground structures can alter the mechanical behavior of surface structures, leading to increased damage during earthquakes. Therefore, it is essential to consider the effects of underground structures. This paper presents a modeling method for soft soil-steel frame structures, with results that are well-correlated with test data, providing a reliable foundation for modeling the entire system. The subway station is introduced, and the underground subway-soft soil-steel frame finite element model is established to study the influence of soft soil and underground subway on the seismic response of the surface steel frame. Key parameters, including soil stiffness, surface structure, earthquake type, and horizontal distance between the underground and surface structures, are taken into consideration. The results show that soft soil has the ability to filter and amplify seismic waves, and its impact on the soil surface varies depending on the specific seismic wave and soil stiffness. Lower soil stiffness leads to a more pronounced amplification effect. Additionally, the presence of an underground subway can scatter and reflect seismic waves, resulting in a 10 % or so increase in peak acceleration at the soil surface under the same ground motion excitation. Finally, the maximum inter-story drift ratio of the steel frame structure increases significantly under the excitation of EL-Centro and Kobe waves, whereas its change under the Taft wave excitation depends on specific parameters.