Corridor-type school buildings, as critical public infrastructure within educational facilities, are of paramount concern regarding their seismic performance. However, seismic damage investigations consistently reveal the susceptibility of this structural type to severe damage and disproportionate collapse. To tackle this critical issue, this study adopted a synergistic methodology integrating component-level quasi-static testing with in-situ structural monitoring. The seismic response characteristics and collapse mechanisms of representative corridor-type school buildings located in high-seismicity regions were investigated. Comparative analyses of mechanical behaviors and failure modes of bare frame components (BF) and infill-frame composite components (IF) were performed through scaled quasi-static tests. Furthermore, a reliable shear force estimation approach was established based on monitored strain and acceleration data, elucidating the intrinsic mechanisms of differential damage among same-story components and the global structural response patterns. The results demonstrate significant disparities in "strong brittle" and "weak-ductile" performance among vertical load-bearing components. Specifically, high-stiffness IF components attract a disproportionate share of seismic shear but possess limited deformation capacity, leading to premature failure under seismic loading and initiating a collapse chain characterized by "performance divergence-shear force concentration-component failure." Consequently, the global ultimate displacement capacity of the structure was governed by these low-deformation-capacity units. This inherent stiffness-deformation incompatibility is identified as a primary driver of the severe structural damage and collapse observed. These findings provide a theoretical foundation and technical reference for the seismic design optimization of corridor type school buildings.

Recent earthquakes have highlighted the vulnerability of reinforced concrete (RC) school buildings with cantilevered outdoor corridors due to the lack of consideration for infill walls in seismic design. In particular, the confining effect of the infill walls causes significant differences in the constitutive behaviour of the various load-bearing components on the same floor of the building, which is often overlooked in current seismic design practices. Based on this motivation, this paper aims to study the efficacy of enhancing seismic performance in buildings by modifying the stiffness ratio between bare columns and captive columns through the widening of bare columns. Using Xuankou middle school as a case study, dynamic time-history analyses were performed on buildings with stiffness ratios ranging from 3.41 to 1. Inter-story drift ratio, performance achievement ratio, and the applicability of the recommended stiffness ratio across different building heights were investigated. The results indicate that infill walls significantly influence column behavior, with captive columns playing a dominant role in the building's seismic resistance. While infill walls enhance performance under low-intensity seismic events, there may be potential overestimations in designs that ignore local infill-frame interactions during rare earthquakes. Although reducing the stiffness ratio from 3.41 to 2.85 yields limited performance improvements, a stiffness ratio of 1.31 ensures compliance with performance-based requirements and is recommended as the optimal value. Buildings with this ratio have good seismic performance across various common heights, with advantages that grow as building height increases. Additionally, excessive stiffness ratios may lead to the redistribution of soft story to other floors. This simplified seismic approach offers valuable insights for optimizing the seismic design and strengthening strategies in reinforced concrete school buildings and similar structures with central-opening.

Destructive earthquakes frequently inflict considerable damage on multistory buildings, with reinforced concrete (RC) frame structures being particularly susceptible. Although the "strong column-weak beam" principle is a common design approach, post-earthquake investigations reveal that failures rarely follow this mode, with damage often concentrated in vertical load-bearing components like wall-column systems instead of beams. This discrepancy raises concerns about the adequacy of current design approaches and highlights the complex interactions between columns, walls, and other structural elements during seismic events. This study aims to investigate the seismic response and collapse mechanisms of soft-story RC frames, emphasizing column behavior, axial compression ratios, and the performance of buildings with soft stories. To achieve this, a shaking table test was conducted on scaled-down RC frame columns, and numerical simulations were developed to analyze displacement responses under varying axial compression ratios and seismic accelerations. Experimental results indicate that bare columns demonstrate considerable deformation capacity, characterized by pronounced shifts in natural frequency during seismic loading. Numerical simulations show that buildings with open first stories exhibit low axial compression ratios, which result in minimal second-order gravity effects and substantial displacement margins. These characteristics reduce the risk of collapse even under high seismic accelerations. The findings suggest that soft-story RC frames, designed based on the story-yield mechanism, exhibit greater collapse resistance than anticipated. For the majority of multi-story buildings, the axial load ratio generally remains below 0.3 when calculated using realistic loading conditions and material strengths. Under these circumstances, the collapse drift ratio can reach values as high as 1/16 or greater. In contrast, the maximum drift ratio observed under a seismic input of 1.0 g is significantly lower, reaching only 1/36. Moreover, building collapse typically involves complex component failure modes with varying structural characteristics, deviating from uniform patterns predicted by traditional design theories. This study provides new insights into the seismic performance and failure mechanisms of multistory frames with soft stories, offering valuable guidance for improving seismic design codes and enhancing the resilience of these structures under earthquake loading.

Seismic damage to buildings reveals significant stiffness effects caused by infill walls, with improper arrangement potentially leading to severe local damage or structural collapse. This study proposes a structural seismic design concept aimed at balancing seismic shear force distribution among RC columns affected by infill walls. Quasistatic tests on two RC frame specimens (a bare frame and a frame with half-height infill walls) and vulnerability assessments of six RC school buildings were conducted. Results indicate that infill walls under windows transform RC columns from bending-dominated to shear-dominated deformation modes, increasing lateral capacity by 77 % but reducing ductility by 42 %. In structures combining bare and captive columns, the seismic shear demand on captive columns is 1.74 times higher than on bare columns, with the lower ductility of captive columns governing the overall seismic response. Structures designed for concept of balanced seismic shear force distribution show surprisingly good performance in fragility analyses. While infill walls mitigate overall structural damage during frequent and precautionary seismic events, structures with more uniform shear distribution exhibit reduced damage susceptibility in rare and extremely rare earthquakes. When the PGA reaches 0.8 g, the addition of infill walls increases the structure's collapse probability by 35 %, while structures using the balanced design concept approach the collapse probability of bare frame structures. These findings highlight the importance of balanced seismic shear force distribution in future structural designs. Additionally, due to the confining effect of infill walls on column deformation, the nominal inter-storey drift ratio (IDRn) was proposed to serve as a new structural damage index. The results using IDRn show higher damage probability estimates than those using IDR, highlighting a potential risk in current seismic design practices that warrants further investigation.

Semi-enclosed buildings, characterized by frame columns only on the street-facing fa & ccedil;ade and masonry walls on the rear and lateral sides, exhibit a distinct "U-shaped open" plan configuration. This building typology is prevalent in multi-story urban structures but exhibits significant seismic vulnerability, prone to severe earthquake damage. This study conducted shaking table tests to investigate the dynamic response characteristics of such structures, aiming to elucidate their collapse mechanisms under seismic excitations. The experimental program was designed based on first-floor damage patterns observed in semi-enclosed buildings stuck by the Luding earthquake in 2022. Testing protocols captured macroscopic phenomena, including motion patterns, component damage states, and strain data at critical locations, under varying peak ground acceleration levels. Microscopic analyses of strain data were performed to evaluate shear force distribution among characteristic components and coaxial elements, as well as the lateral deformation characteristics of structural members. The test results revealed that longitudinal motion dominated the model's dynamic behavior. Seismic shear forces concentrated significantly along the perforated wall axis. This concentration induced early failure initiation at these critical locations. Following the failure of perforated wall axis members, the structural system experienced rapid load-bearing capacity degradation, leading to sequential failure of remaining components and ultimate longitudinal collapse of the test model. The observed failure modes exhibited striking consistency with real-world earthquake damage patterns, validating the experimental model's representativeness and creditability. This research not only identifies the seismic vulnerability mechanisms inherent in semi-enclosed buildings but also provides critical insights for enhancing their collapse-resistant design strategies.

Frame–masonry hybrid structures, though economically practical and widespread in rural China, face significant collapse risks during earthquakes due to shear imbalances from a component mismatch. A severe case was No. 7, Group 1, Detuo Town, after the 2022 Luding earthquake, where damage was concentrated on the ground floor. Numerical modeling revealed that the axis Ⓒ perforated wall, bearing 78% of the seismic shear due to its stiffness, suffered shear failure from geometric and structural factors, triggering a shear concentration–brittle failure chain reaction, pushing the building to near collapse. Meanwhile, the axis Ⓐ frame column, only sustaining 12% shear, sustained minor damage. Based on this typical seismic damage, this study proposes a collapse-resistant design using the deformation saturation theory to achieve balanced shear distribution by adjusting frame column sections. The results showed that compared to the prototype model, the collapse-resistant model (RE) under PGA = 0.4 g saw maximum displacement drop from 16.66 mm to 5.42 mm, which was reduced by 67.5%, the shear share of axis Ⓐ rose from 18% to 45%, the shear force of axis Ⓒ decreased from 70% to 46%, the shear ratio changed from 1:4 to 1:1, and maximum component damage was at 75% of the performance point, indicating significantly enhanced collapse resistance. These findings highlight the importance of balanced seismic shear distribution in preventing shear concentration and brittle failure, validate the deformation saturation theory, and offer a theoretical basis and design reference for the seismic reinforcement of similar hybrid structures.

Following a magnitude M 7.9 earthquake that struck near Mandalay, Myanmar in March 2025, this study investigates the seismic damage inflicted upon the city’s municipal water supply system. The analysis focuses on the failure characteristics of water facilities and pipelines, examines cross-system cascading effects, and proposes corresponding recovery strategies. The main findings are as follows: (1) The damage to water plant facilities, concentrated in ancillary structures and connections due to insufficient seismic measures, demonstrated significant intensity-dependence. Increased seismic intensity not only aggravated structural damage but also compromised core treatment processes, leading to deteriorated water quality. (2) Within the same seismic intensity zone, high-density polyethylene (HDPE) pipes exhibited a significantly lower damage occurrence rate than ductile iron (DI) pipes, highlighting the material’s substantial influence on seismic performance. Moreover, a strong positive correlation was observed between the overall pipeline network damage and the seismic intensity. The average damage rate in Intensity IX zones was 6.84 times that of Intensity VIII zones. (3) A cascading failure, initiated by a power outage, led to water supply disruption, loss of emergency response capability, and elevated secondary risks. This strongly coupled cross-system effect resulted in significant spatiotemporal propagation of disaster impacts. (4) The post-earthquake recovery adopted a phased strategy that prioritized critical facilities. Actions involved rapidly restoring the core supply zone with temporary points, reinstating the water plant’s power supply, and deploying targeted technologies for efficient pipeline repair. The outcomes of this study are expected to provide critical support and a valuable reference for developing earthquake-resilient urban water supply systems.

Frequent seismic events have demonstrated that building collapse is primarily caused by the loss of load-bearing capacity in vertical structural members. In response to this risk, various national design codes have been established. This study conducted field investigations at an earthquake site in Luding County, Sichuan Province, which was struck at a magnitude of 6.8 on 5 September 2022. In this case, the lower x-direction load-bearing wall of the Tianyi Hotel suffered severe shear damage, and the building was on the verge of collapse. However, no obvious damage was seen in the elementary school dormitory. Numerical simulation analysis revealed that during the earthquake, the buildings primarily experienced y-direction displacement in the x-direction, with significant differences in the stress state among different axes. In the model of Tianyi Hotel, the x-direction load-bearing walls suffered shear damage, while the frame columns were still in the elastic stage. At this point, the shear force of the walls was 6–9 times that of the frame columns. Comparing the damage characteristics of the two buildings during the earthquake, it was found that different structural forms lead to different internal force distributions. This phenomenon is further interpreted through the principle of “deformation saturation”, with core structural components being modeled and tested using quasi-static experiments. The results indicated substantial differences in material properties among different structural forms, including variations in lateral stiffness, ultimate load-bearing capacity, and maximum displacement. Moreover, at the same floor level, components with smaller ultimate displacements are decisive of the overall structural stability. To ensure seismic resilience and stability, it is essential to consider not only the load-bearing capacity but also the rational arrangement and cooperative interactions between different components to achieve a balanced distribution of overall stiffness. This approach significantly enhances the building’s resistance to collapse.

Recent earthquakes have highlighted the vulnerability of infilled reinforced concrete structures due to the insufficient consideration of infill masonry walls' contribution to strength and stiffness. This study presents a novel refractory straw block (RSB) designed to address these challenges and improve the seismic performance of reinforced concrete (RC) frames. Unlike traditional infills, RSB is characterized by low-elastic-modulus, lowdensity, and high-ductility. Quasi-static tests were performed on three types of frames: unfilled, infilled hollow grouted bricks (HGB), and infilled RSBs. Failure model, stiffness, and load-displacement response of three specimens were investigated and analyzed. The results indicate that RSBs as infill material does not alter the failure mode and constitutive relationship of bare frame, while HGBs leads to shear failure. The peak load for the specimen IF-HGB was 69.3 kN at 1.1 % drift, compared to 38.8 kN at 2.4 % drift for the specimen IF-RSB, and 36.4 kN at 2.0 % drift for the specimen BF. The strengths of specimens IF-HGB and IF-RSB were 1.90 and 1.07 times that of specimen BF, respectively. The stiffness of specimen IF-HGB was 3.7 times that of the other specimens, but its allowable displacement was only 61 % of theirs. Dynamic time-history analyses were also performed on structures with no longitudinal infill (BF), with RSBs (SBF), and with fired bricks (FBF). At the design level of rare events (magnitude 8, PGA 400 gal), severe damage occurred, but collapse was limited. When the PGA increased further, the collapse probability of model FBF rose rapidly, whereas the collapse probabilities of models SBF and BF remained low and similar. Accounting for the confining effect of walls, model FBF showed a higher probability of severe damage than models SBF and BF, particularly under minor earthquakes. The maximum inter-storey drift ratio of the model SBF and FBF were respectively 1.2 times and 1.7 times that of the model BF, which shows that straw blocks as infill can greatly avoid the effect of infill on the seismic behavior of the structure. The study also emphasized the often-overlooked confining effect of masonry on columns, which can lead to unrealistic damage assessments and seismic shear force distributions.

为研究不同砌筑材料对钢筋混凝土框架(RC框架)抗震性能的影响,采用有限元分别建立纯框架、加气混凝土砌块和秸秆草砖 3 种不同类型的填充墙框架有限元模型,考察不同材料、不同砌筑高度对RC框架抗震性能的影响.数值模拟结果表明,不同砌筑高度的加气混凝土砌块对RC框架受力性能影响较大,由于填充墙的存在,柱变为短柱,最大承载力下降约为 42％,而秸秆草砖填充墙框架耗能变化率只有3.43％,与纯框架的受力、变形基本相同.与加气混凝土砌块相比,采用秸秆草砖作为砌块,其对RC框架的受力影响较小,秸秆草砖作为填充墙原料优于加气混凝土砌块,建议工程采用秸秆草砖作为砌筑材料.

2022年1月2日云南省宁蒗县发生Ms5.5地震,地震位于川滇边界处泸沽湖附近.历史上该地区曾多次发生5.5级左右的中强地震,震区构造复杂,NW向和NE向断裂展布相互交织,构成棋盘格状.据野外地质调查,震中区附近NW向永宁断裂和NE向日古鲁-岩瓦断裂具有明显的晚更新世活动迹象,同时对永宁新生代构造盆地和新生界具有明显的控制作用.根据泸沽湖西侧地质钻孔推测永宁盆地内尚发育1条与永宁断裂平行的NW向隐伏断层.地震震源机制解、同震位移场、地震烈度分布特征及地震现场破坏调查结果表明,此次地震与NW向永宁活动断裂密切相关.

填充墙具有显著的刚度和承载力贡献.建筑结构震害调查发现,不开洞横墙的破坏程度远小于开洞纵墙的破坏程度,从宏观现象可判断大部分多层建筑的破坏主要由结构纵向运动造成.为研究横墙在地震作用下的性能及其对结构整体动力响应的影响,以经受2021年5月21日云南漾濞6.4级地震震害的花椒园小学教学楼为研究对象,按当地抗震计算参数进行弹塑性时程分析.采用等效斜压杆模拟横向填充墙,设置无填充墙框架结构、带黏土砖墙的框架结构、带空心砖墙的框架结构和带加气混凝土砌块填充墙的框架结构模型,选取10组地震波横向输入.研究结果表明,4种结构自振周期均处于具有统计学意义的平台段,平均加速度响应较接近,质量和刚度变化不会使结构加速度产生规律的变化;受结构自重影响,无填充墙的框架结构底部剪力小于带填充墙的框架结构,带填充墙的框架结构位移远小于无填充墙的框架结构;带有多道不开洞横墙的多层框架结构的破坏主要是由结构纵向破坏引起的.

The relative values of lateral stiffness and ultimate limit state of bearing capacity of vertical members are defining factors of the seismic failure or collapse mode of structures. This paper focuses on how the different construction sequences of infilled walls and frame columns influence the seismic performance of frame structures based on the low-cycle reciprocating loading tests of six single-layer two-span frame structure models with a ratio of 1:4, including two frame models without infilled walls (F model), two frame models with walls built later (LW model), and two frame models with walls built first (FW model).According to the test results, different construction sequences of infilled walls have a significant impact on the seismic performance of frame structures. The FW model introduces the process of "building the wall first and then casting the column" with the wall and the column highly combined with each other and the infilled wall involved in the internal force distribution of the frame structure, boasting the largest bearing capacity and initial stiffness; LW model is built by "pouring the column first and then building the wall" with a low combination between wall and column, its bearing capacity and initial stiffness second to FW model; F model has the smallest bearing capacity and initial stiffness. Shear failure and poor ductility are found in the FW model due to the restraint effect of the infilled wall; bending failure in the F model with a large displacement but good ductility; shear failure tends to appear in the LW model structure with the failure in bonding between reinforcement and concrete in the end and good ductility. The research results can provide a reference for the elastic-plastic seismic response analysis considering the interaction of infilled wall and frame.

多层RC框架结构在我国城镇中应用广泛且量大面广,尤其是在中小学教学楼十分常见,由于建筑使用功能的需求,多采用外廊式框架结构.在历次破坏性地震的震害调查发现,中小学教学楼的震害较严重,甚至出现倒塌.2021年05月21日21时48分,云南大理州漾濞县发生6.4级地震,震害调查表明,有些中小学教学楼较新,严格按照抗震设计规范进行建造的,虽未倒塌,但也暴露出一些较普遍的问题.通过对教学楼震害调查研究,分析了结构构件破坏的原因,提出建筑结构抗震的相关建议.

墙体作为结构体系中的重要组成部分,由于刚度大、变形能力差、与梁柱连接方式等原因影响了结构安全.秸秆草砖因其具有轻质、易变形、节能等特性,受到中外学者的广泛关注,对此开展了大量研究,并将其应用于现代建筑中.综述了中外关于秸秆草砖的力学性能、耐火隔热性、节能保温性、防水防腐性及抗震性的研究现状,分析了现阶段存在的问题,提出了未来研究方向的建议.

外廊式教学楼是中小学校典型的建筑形式.汶川地震后,外廊式教学楼震害引起大量研究人员重视.2021年5月21日21时48分,云南大理州漾濞县发生6.4级地震,本文作者详细调查了位于漾濞县的4所典型框架结构外廊式教学楼,以震害较为严重的漾濞一中和花椒园小学为例,分析了结构各部位发生破坏的原因.以震害现象为佐证,得出以下结论:由于横墙的约束,楼板沿纵向平动,各轴构件的本构关系可在同一坐标系下进行对比分析,结构破坏取决于构件沿纵向的极限位移.并在此基础上,从新的角度探讨了多层建筑的抗震能力.

由于老旧砖房服役年代较长,其安全问题需要引起足够的重视.随着物联网的兴起,将物联网技术应用到老旧砖房的安全在线监测中具有重要意义.论文以物联网技术在建筑结构中的监测应用为主,设计了一套砖房安全监测系统,介绍了该系统组成的传感器、数据传输、系统组网等技术,并通过工程应用案例验证该系统的有效性.

混凝土梁(RC梁)作为结构体系中的主要受力构件之一,常因各种原因出现劣损影响到结构安全.FRP材料因其具有轻质、高强、耐腐蚀等特性,已被广泛应用于RC梁的加固工程中.目前,FRP加固RC梁的研究较为深入.本文综述了国内外学者关于FRP加固RC梁的静力性能以及抗火性、抗冲击性的研究现状,分析了现阶段研究存在的问题,提出了对未来研究方向的建议.

桥梁承台施工时,通常由于水泥水化热过大容易导致混凝土开裂,混凝土的温度监测是施工过程的重要环节.论文将云平台、传感器、无线传输技术应用到承台施工温度监测中,采用数字化温度传感器和公有云服务器搭建了自动化监测系统,并在工程实践中得到应用.实践验证了该监测系统的可行性,可以实现大体积混凝土温度监测的自动化和实时化功能,并应用Team Viewer来进行数据远程访问,降低了数据共享的软件成本.

2020年5月18日巧家县发生5.0级地震,结合震区背景信息和现场调查,详细阐述此次地震烈度分布和房屋震害特征,并计算各类结构房屋的震害指数和破坏比.调查发现,本次地震的最高烈度为Ⅵ度,长轴呈NW向,与灾区地震地质构造背景、仪器烈度分布具有较好的一致性.对比分析本次地震与昭通地区、云南其他地区近年来大小相近的历史地震Ⅵ度区震害指数,结果表明,本次地震房屋震害指数相较于昭通其他地区明显偏低,但比云南其他地区偏高.分析认为,近年来巧家县各项房屋改造工程切实提高了当地房屋抗震水平,但仍需加强房屋改造建设,尤其是加快推进老旧房屋拆除及新房建设工作,进一步提升房屋抗震能力.