Safety Evaluation Of Buildings Research Articles

Building Safety Evaluation and Improvement for Northern Vietnam Mountainous Environments Empirical Study Combining Japanese Experience with Local Conditions

This study addressed the insufficient structural strength and inadequate disaster resistance in building designs in the mountainous regions of Northern Vietnam. By integrating Japanese construction experience with local conditions, we proposed optimized building structures and simplified safety evaluation methods. Through an analysis of climate, terrain, geological hazards, soil conditions, and construction material costs, building design and foundation construction were optimized, and these optimizations were validated through wind tunnel experiments and finite element analysis. The results indicated that the optimized structures exhibited superior wind load stability, with external wind pressure coefficients ranging from −1.5 to −0.7, compared with the traditional structure’s range of −1 to −3.5. The redesigned foundation improved landslide resistance, reducing excavation and foundation construction costs relative to Japanese methods. The foundation’s safety factor reached 4.42–5.13, surpassing the standard of 2.5, and the retaining wall’s sliding resistance safety factor reached 1.87, exceeding the requirement of 1.5. These enhancements dramatically boosted building safety under extreme weather conditions. This study provides practical solutions for building design in Vietnam’s mountainous regions and serves as a valuable reference for similar research in other developing countries, underscoring significant practical and social implications.

Computer vision-based post-earthquake inspections for building safety assessment

Assessing the safety of earthquake-affected buildings is a critical structural health monitoring task that facilitates the timely response to present dangers and reduces potential threats to life and property. However, post-earthquake time constraints and harsh environmental conditions mean that images and videos taken on-site are frequently affected by poor resolution and blurriness, which may negatively affect the accuracy and usefulness of artificial intelligence image recognition tools. In this study, a HybridGAN model was developed that incorporates ESRGAN for resolution improvement and DeblurGANv2 for blurriness improvement. Additionally, a transfer learning U-Net (TF-Unet) was integrated to detect building components (i.e., columns and structural walls), classify building damage types, and identify building damage levels. Based on recognition results from three case studies and the relevant Taiwan codes, an automated system for building safety evaluation was proposed. The model was trained to directly classify and recognize the level of building component damage. The mean Intersection over Union (mIoU) results for the column and structural wall using the testing dataset were 81.326 % and 57.009 %, respectively. The pre-trained model was used to predict three case studies to test the capability of TF-Unet to handle real-word datasets.

Integrative building safety evaluation to mitigate disaster risks: a case study on public-use buildings in Seoul

ABSTRACT Recognizing potential hazards is imperative for devising pragmatic building inspection and management strategies. However, existing safety evaluation standards across diverse fields have inherent limitations in ensuring overall building safety. Chained and cascading damages following a catastrophic disaster necessitate comprehensive safety management. Thus, this study derived evaluation criteria and determined their priority to assess building safety against various hazardous events in urban settings. This case study targeted Seoul’s public-use buildings with high risks of potential harm to many regular users. Moreover, this study aggregated evaluation categories from existing inspection and certification standards into field-specific groups, including architecture, fire safety, electrical systems, gas systems, vertical transportation, and crime prevention. This categorical evaluation was further analyzed based on their importance for preventing disasters and minimizing damage, emphasizing fire safety as the most essential for securing building safety. In addition, categories evaluated from a preventative perspective hold significantly greater importance than those focused on mitigating damage. This finding underscores the need for proactive monitoring and enhanced building safety across six fields before a disaster strikes. The integrated assessment method facilitates determining which areas are well managed or need improvement. Furthermore, this approach enables efficient building safety enhancement by prioritizing field-specific or evaluation criterion-specific areas.

IOT based Fire Detection System with Automatic and Manual Extinguishing System

A Novel fire extinguishing monitoring and control system is proposed in this paper. The system combines online monitoring of fire extinguishing information based on internet of things (IOT), early fire warning and alarm system with building safety evaluation, which are designed to acquiring the real-time information of fire extinguishing working condition, improving the reliable prediction mechanism in traditional fire monitoring system. A perception terminal based on IOT is developed and the fire real-time monitoring and control system is designed in this paper. The novel system can acquire the real-time working condition information of fire extinguishing facilities, such as pipe flow, pressure, temperature and humidity of the environment, current and voltage of the electric equipment, valve switch, relay action, alarming message, it can upload the collected data to the monitoring center through the (Client /Server) architecture. Based on these data, an electrical early fire warning model based on neural network is proposed. A fire safety evaluation model based on ontology with the usage of protege is established, which facilitate the on-line monitoring and control of building fire protection information, the prediction of electrical fire and improve building safety level evaluation.

A General Framework for the Impact of Shield Tunnel Construction on Existing Tunnel in Soil

During the excavation process of shield tunneling, it is inevitable that the surrounding soil mass is disturbed, which will affect the adjacent structures. This paper proposes a general framework for the impact of shield tunneling construction on existing tunnels. First, the impact partition of shield tunneling construction regarding adjacent tunnels and buildings is established by a three-dimensional numerical analysis method. Then, the displacement of adjacent tunnels and buildings is predicted using fuzzy gray theory. Finally, based on the results of a numerical simulation and experiment, the risk classification standard of adjacent buildings is established. This framework has certain reference significance and value for the deformation prediction and safety evaluation of adjacent buildings.

Numerical Simulation Analysis of Chinese Timber Frame Ancient Buildings - An Example of the Hall of Supreme Harmony in the Forbidden City

Chinese ancient architecture is renowned for its unique large wooden structures and standards. However, the safety of the wooden structures in the Forbidden City has gradually deteriorated over long-term use. At present, most building safety evaluation methods rely on qualitative assessments rather than quantitative identifications. In the process of conducting safety evaluations, it is necessary to conduct sufficient analysis and judgment of building damage to determine the safety status of ancient buildings. To ensure the safety of the buildings, this study takes the Hall of Supreme Harmony in the Forbidden City as an example, using numerical simulation methods to analyze the components of Chinese wooden ancient architecture through finite element analysis, with the aim of quantitatively protecting China's traditional architectural cultural heritage. This study provides a scientific basis for the protection of China's traditional architectural cultural heritage and has high practical significance. The results showed that the deformation peak and internal force were within the allowable range according to relevant specifications.

Safety assessment of ancient buddhist pagoda induced by underpass metro tunnel blasting vibration

In the blasting excavation project of the subway tunnel in the urban area, ensuring the safety of the surface buildings (structures) above the crossing area is the key concern. This paper is based on the blasting project of the ancient pagoda (Shengxiang Pagoda) under the tunnel between Pengliuyang Road Station and Simenkou Station of Wuhan Metro Line 5. To protect the integrity of the ancient buildings, this paper mainly adopts the numerical simulation method to analyze the dynamic response characteristics of the tower above the subway and realizes the safety assessment of the tower based on the maximum principal stress and vibration velocity control. The results show that the maximum error rate between the measured data and the numerical simulation results is only 11.9 %, which verifies the reliability of the numerical model and parameters. In the process of blasting vibration propagation, the vibration velocity of the tower body is affected by the whiplash effect and the elevation amplification effect. The vibration velocity of the tower bottom is 0.29 cm / s, and the vibration velocity of the tower tip reaches 4.29 cm / s. The vibration velocity of the upper part of the tower is much larger than that of the lower part. The stress distribution of the tower body is accompanied by stress concentration, with the maximum reaching 0.0442 MPa and the minimum only 0.014 MPa. The safety assessment of the ancient pagoda from the aspects of structural strength and vibration velocity can determine that the structure is safe under this condition. The research results are of great significance to the analysis of dynamic response characteristics and safety evaluation of ancient buildings under blasting load in urban complex environments.

Detection and analysis of an eave purlin of the timber building eroded by carpenter bees based on computed tomography

To explore the harm of carpenter bee nests to timber buildings, an eave purlin of Wu’s house, the seventh batch of national key cultural relics in China, was taken as the research object. A CT (computed tomography) device was used to collect the projection data of wood components, and VGSTUDIO MAX3.2 software was used to reconstruct multiple transverse sections, radial sections, tangential sections, and 3D (three-dimensional) images of an eave purlin. The results showed that carpenter bees eroded a timber building randomly, but they usually nested along the length of eave purlin. The wood in the middle of an eave purlin is more vulnerable to carpenter bees than the end. Carpenter bee nests are usually not connected, and the volume of nests accounts for 3% to 4% of the eave purlin. The eave purlin is applied with an orientation and a torsion force. The position of the maximum hot spots of the stress occurs at holes and the large cracks, indicating that carpenter bee nests have a great impact on the mechanical properties of timber buildings. The research results of this paper provide reference for the safety evaluation and preventive protection of timber buildings.

Development and Validation of a Post-Earthquake Safety Assessment System for High-Rise Buildings Using Acceleration Measurements

After a major seismic event, structural safety inspections by qualified experts are required prior to reoccupying a building and resuming operation. Such manual inspections are generally performed by teams of two or more experts and are time consuming, labor intensive, subjective in nature, and potentially put the lives of the inspectors in danger. The authors reported previously on the system for a rapid post-earthquake safety assessment of buildings using sparse acceleration data. The proposed framework was demonstrated using simulation of a five-story steel building modeled with three-dimensional nonlinear analysis subjected to historical earthquakes. The results confirmed the potential of the proposed approach for rapid safety evaluation of buildings after seismic events. However, experimental validation on large-scale structures is required prior to field implementation. Moreover, an extension to the assessment of high-rise buildings, such as those commonly used for residences and offices in modern cities, is needed. To this end, a 1/3-scale 18-story experimental steel building tested on the shaking table at E-Defense in Japan is considered. The importance of online model updating of the linear building model used to calculate the Damage Sensitive Features (DSFs) during the operation is also discussed. Experimental results confirm the efficacy of the proposed approach for rapid post-earthquake safety evaluation for high-rise buildings. Finally, a cost-benefit analysis with respect to the number of sensors used is presented.

Deformation Response and Safety Evaluation of Buildings Affected by Subway-Station Construction

Based on the sand and pebble stratum in the Beijing area, this paper studies the interaction between deep-foundation-pit excavation for subway stations and surrounding buildings using an orthogonal test. Moreover, it considers the relative position relationship between buildings and how the foundation pit is set up as well as different design schemes for foundation pits and the surrounding buildings. Results show that the horizontal distance s between the building and foundation pit and stiffness of the building itself have a clear impact on the differential settlement δij and relative deflection Δ, and the degree of deformation of the building near the corner of the foundation pit is complex. Simultaneously, based on numerical simulation results, the deformation characteristics and degree of deformation of the building under different relative position relationships with the foundation pit are analyzed. Finally, by establishing a relationship among the comprehensive deformation index Dj, surrounding environmental safety evaluation index Sj, and scheme safety grade Lj, a multiangle safety evaluation method for buildings affected by foundation-pit construction is formed, which can provide a reference for the research and design of similar projects.

A Machine Learning Framework for Assessing Seismic Hazard Safety of Reinforced Concrete Buildings

Although averting a seismic disturbance and its physical, social, and economic disruption is practically impossible, using the advancements in computational science and numerical modeling shall equip humanity to predict its severity, understand the outcomes, and equip for post-disaster management. Many buildings exist amidst the developed metropolitan areas, which are senile and still in service. These buildings were also designed before establishing national seismic codes or without the introduction of construction regulations. In that case, risk reduction is significant for developing alternatives and designing suitable models to enhance the existing structure’s performance. Such models will be able to classify risks and casualties related to possible earthquakes through emergency preparation. Thus, it is crucial to recognize structures that are susceptible to earthquake vibrations and need to be prioritized for retrofitting. However, each building’s behavior under seismic actions cannot be studied through performing structural analysis, as it might be unrealistic because of the rigorous computations, long period, and substantial expenditure. Therefore, it calls for a simple, reliable, and accurate process known as Rapid Visual Screening (RVS), which serves as a primary screening platform, including an optimum number of seismic parameters and predetermined performance damage conditions for structures. In this study, the damage classification technique was studied, and the efficacy of the Machine Learning (ML) method in damage prediction via a Support Vector Machine (SVM) model was explored. The ML model is trained and tested separately on damage data from four different earthquakes, namely Ecuador, Haiti, Nepal, and South Korea. Each dataset consists of varying numbers of input data and eight performance modifiers. Based on the study and the results, the ML model using SVM classifies the given input data into the belonging classes and accomplishes the performance on hazard safety evaluation of buildings.

A Multilevel Approach for the Cultural Heritage Vulnerability and Strengthening: Application to the Melfi Castle

This study outlines a procedure for the seismic safety evaluation of historical buildings for engineers and architects that commonly work on buildings belonging to cultural and architectural heritage. The procedure is characterized by two interrelated phases: (a) building knowledge acquisition and (b) structural behavior analysis and safety assessment. The seismic safety evaluation strongly depends on the first phase, whose data can be obtained according to a multi-disciplinary approach based on five steps: (1) critical-historical analysis; (2) photographic documentation and geometrical survey; (3) structural identification and material survey; (4) foundation and soil survey; and (5) cracking pattern and structural integrity analysis. The proposed method was applied to the evaluation of the seismic safety of the Castle of Melfi (PZ, Italy). Comprehensive and multi-disciplinary knowledge of this monument greatly facilitated an accurate seismic analysis of this monument, which was conducted both at a local and global level using a linear kinematic analysis and non-linear static (pushover) analysis, respectively.

Rapid postearthquake safety evaluation of buildings using sparse acceleration measurements

After a seismic event, buildings need to be inspected to confirm their safety prior to reoccupation. As such, the rapid evaluation of the condition of individual buildings is important for minimizing disruption to lives and business. However, traditional manual inspection by experts is laborious and time-consuming. Structural health monitoring provides the potential to accelerate the required evaluation. This article proposes a cost-effective approach for rapid safety evaluation of buildings after seismic events using sparse acceleration measurements. First, a damage-sensitive feature is defined that can be used to infer the condition of buildings. Herein, the maximum interstory drift angle is proposed as a reliable damage index to classify the safety of buildings after seismic events. A convolutional neural network is then employed to uncover the complex relationship between the damage-sensitive features and the building condition. A five-story steel building is considered to validate the proposed approach. First, a three-dimensional nonlinear model of the building is created. To generate the required training data, a simplified nonlinear model is developed, along with a corresponding linear model, as use of the three-dimensional model is too computationally expensive. The training data for the convolutional neural network incorporates uncertainties in both the analysis model and the ground motion. Initial evaluation is conducted using the simplified nonlinear model, while final validation of the proposed approach is performed using the results of the three-dimensional nonlinear analysis model subjected to historical earthquakes. The results demonstrate the ability of the proposed approach to accommodate differences between the in-situ structure and the analysis model, as well as the efficacy of this approach for rapid postearthquake safety evaluation of buildings.

Flexural deformation characterization of glass panel in curtain walls based on digital image correlation technique

In architectural engineering, full-field mechanical characterization for the outer surface of buildings has been increasingly an essential part of the building safety evaluation, especially for high-rise buildings. However, due to the inherent nature of local and contact measurements of some traditional methods, both measurement accuracy and detected regions are generally quite limited. In this paper, the non-contact digital image correlation (DIC) technique was employed to implement full-field surface flexural deformation characterization for the glass panel of curtain wall system. Firstly, a set of experimental apparatus was designed to obtain the digital speckle image sequences of the tested glass panel under wind load conditions. Secondly, full-field deformation of the glass panel was quantitatively calculated and compared with those data resulted from finite element analysis (FEA) and some traditional measurement devices including strain gauges and digital indicators, which demonstrated that the introduced DIC method not only was capable of achieving full-field flexural deformation measurement for the glass panel, but also could obtain comparable measurement results in comparison with the conventional methods. Consequently, full-field displacement and strain of the glass panel were evaluated, so that surface deflections and curvatures of the panel under wind load conditions were carefully analyzed, by which the wind resistance performance for the glass panel of curtain wall system could be readily characterized.

Post-earthquake building safety evaluation using consumer-grade surveillance cameras

This paper demonstrates the possibility of evaluating the safety of a building right after an earthquake using consumergrade surveillance cameras installed in the building. Two cameras are used in each story to extract the time history of interstory drift during the earthquake based on camera calibration, stereo triangulation, and image template matching techniques. The interstory drift of several markers on the rigid floor are used to estimate the motion of the geometric center using the least square approach, then the horizontal interstory drift of any location on the floor can be estimated. A shaking table collapse test of a steel building was conducted to verify the proposed approach. The results indicate that the accuracy of the interstory drift measured by the cameras is high enough to estimate the damage state of the building based on the fragility curve of the interstory drift ratio. On the other hand, the interstory drift measured by an accelerometer tends to underestimate the damage state when residual interstory drift occurs because the low frequency content of the displacement signal is eliminated when high-pass filtering is employed for baseline correction.

Fire Safety Evaluation of Urban Buildings

As buildings have been getting taller and incorporating more intelligent designs due to industry development and population growth, property damage and the numbers of casualties resulting from fires are increasing, which requires safety evaluations that involve engineering analysis methods. This study analyzes the use of safety measures against fire hazards, by conducting fire simulations to calculate the visibility range and radiant/convective heat in CO/CO2/smoke, and by performing evacuation simulations to analyze the ASET(Available Safety Egress Time)/RSET(Required Safety Egress Time). From the results of the fire/evacuation simulations, it is possible to estimate the impacts that fire hazards (e.g. toxic gases and temperatures) can have on the occupants’ safety, to examine the feasibility of the evacuation/fireproof equipment in buildings for unspecified individuals, and to establish an optimized evacuation plan to minimize damage or loss of life. It is expected that fire simulations will enable the following activities: risk impact evaluation analyses, laboratory safety inspections, establishment of safety assessments for construction works, and future continuous research studies linked to super high-rise buildings.

Improving Post-Earthquake Building Safety Evaluation using the 2015 Gorkha, Nepal, Earthquake Rapid Visual Damage Assessment Data

A Rapid Visual Damage Assessment was initiated in the direct aftermath of the 2015 Gorkha earthquake to assess the safety and damage of residential buildings in the areas affected by the earthquake. Over 30,000 paper assessment forms have been subsequently digitized. The collected data set allows comparison of the observed damage to the residential building stock to the damage expected using existing fragility curves. Under certain conditions and respecting certain limitations, the post-earthquake building safety and damage data can be used to update the existing fragility functions for the Nepalese building stock. Recommendations are made for the improvement of post-earthquake building safety assessments in Nepal in order to: (1) make data collection more consistent, (2) increase the accuracy of the collected data, and (3) make more effective use of the collected data after future earthquakes.

Post-earthquake safety evaluation of buildings in Portoviejo, Manabí province, following the Mw7.8 Ecuador earthquake of April 16, 2016

This paper describes the post-earthquake safety assessments conducted by the European Union Civil Protection Team (EUCPT) following the Mw 7.8 Ecuador earthquake of April 16, 2016. The mission of the structural engineers within the EUCPT took place from April 22 to May 7, 2016. Several activities were performed: (i) rapid post-earthquake safety evaluations of buildings, (ii) demolition verification, (iii) safe road access, and (iv) detailed post-earthquake safety assessments of critical buildings. Despite the small number of structural experts, more than 1000 buildings were inspected in Portoviejo and approximately 150 in Pedernales. Several lessons were identified during this mission, including the need of embedding local experts in foreign teams and the importance of having preparedness programs on post-earthquake assessment both for technicians and emergency managers. The efforts of the EUCPT benefitted largely from a Disaster Risk Reduction (DRR) pilot project which was underway at the time of the earthquake. While the project was not yet completed, such investment in DRR benefitted the disaster response efforts, even in areas which were not directly involved in the program.

Safety Evaluation of Urban Shield Hyperbolic Tunneling Construction Underneath Buildings

Safety Evaluation of Urban Shield Hyperbolic Tunneling Construction Underneath Buildings

Virtual Inspector and its application to immediate pre-event and post-event earthquake loss and safety assessment of buildings

We previously introduced the Virtual Inspector, which is a decision-support system that follows current US guidelines for post-earthquake damage and safety evaluation of buildings in order to calculate probabilities that a building will be tagged with red, yellow or green safety placards after earthquake shaking of the building. The procedure is based on an existing probabilistic methodology for performance-based earthquake engineering that involves four analysis stages: hazard, structural, damage and loss analyses. In this paper, we propose to integrate the Virtual Inspector into an automated system for immediate pre- and post-earthquake loss and safety assessment in a building. This system could be combined with an earthquake early warning system to assist in an automated decision analysis for initiating safety and loss mitigation actions just before the arrival of earthquake shaking at the building site. The Virtual Inspector can also be used immediately after strong earthquake shaking to provide an automated probabilistic safety and loss assessment to support risk decision making related to possible building closure and the cost of recovery to bring the building back to an operating condition. The proposed theory for these extensions of the Virtual Inspector is illustrated using an example based on a previously studied benchmark office building.