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Ground motions induced by strong, distant earthquakes may contain extremely long-period seismic waves that have a dominant period of up to 10 s. In general, these long-period seismic waves have small amplitudes and do not endanger the safety of building structures and civil infrastructures. However, they may bring unexpected shutdown of some vibration (displacement)-sensitive equipment (such as the wafer scanners in high-tech fabs), which can cause production loss. In this study, seismic waveforms collected from broadband seismometers distributed in Taiwan were used to investigate the ground motion characteristics of the collected distant earthquakes (with an epicenter distance of over 1000 km). The time-variant dominant frequency was extracted using moving window wavelet packet transform to monitor significant long-period seismic waves from the preevent data of each seismic event. The slope of the Arias intensity and the slope index of the recorded seismic waves were also developed to detect the potential accumulation of vibration energy increasing with respect to time and amplitude. The proposed index was used to detect the features of significant distant earthquakes, and it provides a mechanism to prevent unexpected shutdown of displacement-sensitive equipment. Finally, the proposed approach is discussed in relation to the damage severity of high-tech fabs. [ABSTRACT FROM AUTHOR]

It is an acknowledged fact that historical centers, given its significance from the cultural and architectural viewpoint, bring further challenges in terms of maintenance planning, survey, and safety assessment. The preparation of an adequate investigation plan and the extent of data to be collected is highly reliant on many aspects, such as the category of the architectonic asset, the importance of the heritage site, or the resources available, for example. In what regards the seismic response assessment of urban cultural heritage assets located in historical centers, the amount and detail of data also depend on this article, scale of assessment, and current state of conservation and occupation. Within this framework, this article provides an overview of the state of the art of investigation techniques currently used in survey operations, which are currently available for improving the knowledge level of urban cultural heritage assets within historical centers, as a supporting tool for the seismic response assessment of such singular assets. Finally, acknowledging the lack of accuracy when evaluating the seismic response of an asset enclosed in aggregate as an isolated structure, this article also focuses on the identification of the main particularities inherent to buildings enclosed in aggregate. [ABSTRACT FROM AUTHOR]

How can we find patterns and anomalies in a tensor, i.e., multi-dimensional array, in an efficient and directly interpretable way? How can we do this in an online environment, where a new tensor arrives at each time step? Finding patterns and anomalies in multi-dimensional data have many important applications, including building safety monitoring, health monitoring, cyber security, terrorist detection, and fake user detection in social networks. Standard tensor decomposition results are not directly interpretable and few methods that propose to increase interpretability need to be made faster, more memory efficient, and more accurate for large and quickly generated data in the online environment. We propose two versions of a fast, accurate, and directly interpretable tensor decomposition method we call CTD that is based on efficient sampling method. First is the static version of CTD, i.e., CTD-S, that provably guarantees up to 11× higher accuracy than that of the state-of-the-art method. Also, CTD-S is made up to 2.3× faster and up to 24× more memory-efficient than the state-of-the-art method by removing redundancy. Second is the dynamic version of CTD, i.e. CTD-D, which is the first interpretable dynamic tensor decomposition method ever proposed. It is also made up to 82× faster than the already fast CTD-S by exploiting factors at previous time step and by reordering operations. With CTD, we demonstrate how the results can be effectively interpreted in online distributed denial of service (DDoS) attack detection and online troll detection. [ABSTRACT FROM AUTHOR]

The estimate of concrete compressive strength is a major aspect in the assessment of reinforced concrete existing structures since it involves safety issues. The method of extracting concrete cores from the buildings under investigation is considered in this paper. In the first part, a brief review concerning procedures proposed by international technical codes as well methods available in the scientific literature, is made. In particular, formulations proposed for the determination of the actual concrete strength, starting from the one obtained from laboratory tests on cores, are examined. Special attention is devoted to the various factors affecting the estimate of the actual strength and relative correction coefficients. In the second part, the considered procedures are applied to a case study concerning a school building in Tuscany; comparison among different formulations allows some considerations on the reliability of the adopted procedures. [ABSTRACT FROM AUTHOR]

The regulatory landscape related to building control in Australia is complex. While there is a single performance based technical requirement in common for building work there are eight state and territory governments and the commonwealth government, each with a different legislative framework for dealing with development activities. Each has adopted some form of private participation model. In the view of AIBS, Australian government structures and policy implementation with respect to building control is not working. In September 2017, AIBS released a Policy: 'Building Regulatory Reform in Australia', a document describing a legislative framework, which has the capacity to deal with emergent issues such as non-conforming building products in a way that supports the benefits of private participation. This paper sets out why and how AIBS has developed its policy, the policy content and how the content interrelates to other elements of the legislative landscape. It describes the importance of elements in supporting the successful implementation of a performance based technical code and how this will support the competitiveness of Australia's economy. It also provides the integral components for a robust building control system that supports a sustainable building industry providing better outcomes for consumers and industry. [ABSTRACT FROM AUTHOR]

A study of a 60-storey reinforced concrete residential building was undertaken to evaluate the propping schemes supporting the flat slabs. Relevant data necessary for evaluation were acquired from the construction site. Based on the obtained data, a simple methodology to formulate the alternative propping schemes is presented in this paper. The propping scheme designed at the construction site for a 10 d slab cycle is analysed and possible alternative schemes are proposed. The primary objectives of the alternative schemes are to ensure safety and economy, and to minimise the number of construction activities on each level. A comparison of the propping schemes suitable for different slab cycle durations was also performed. It is shown that specific slab cycle durations are comparatively more cost-effective. [ABSTRACT FROM AUTHOR]

Recent earthquakes have demonstrated that buildings with irregular configuration are more vulnerable to earthquake damage. Moreover, the configuration irregularities introduce major challenges in the seismic design of building structures. One such form of irregularity is the presence of re-entrant corners and torsional irregularity that causes stress concentration due to sudden changes in stiffness and torsion amplification in buildings. Constructive research into re-entrant corner and torsion-irregular buildings is therefore needed to evaluate the seismic response demands for reducing the potential damage. The aim of the study reported in this paper is to grasp the seismic performance of L-shaped irregular buildings with moment-resisting frames through an evaluation of the irregularity effects on measured seismic response demands. The results for inter-storey drift, storey shear force, overturning moment, torsion-moment responses at the base and along the building height, top-floor displacement and torsional irregularity coefficient prove that buildings with irregularity are more vulnerable than those with a regular configuration resulting from stress concentration and coupled lateral-torsional behaviour. [ABSTRACT FROM AUTHOR]

Every minute counts in an event of fire evacuation where evacuees need to make immediate routing decisions in a condition of low visibility, low environmental familiarity, and high anxiety. However, the existing fire evacuation routing models using various algorithm such as ant colony optimization or particle swarm optimization can neither properly interpret the delay caused by congestion during evacuation nor determine the best layout of emergency exit guidance signs; thus bee colony optimization is expected to solve the problem. This study aims to develop a fire evacuation routing model “Bee-Fire” using artificial bee colony optimization (BCO) and to test the routing model through a simulation run. Bee-Fire is able to find the optimal fire evacuation routing solutions; thus not only the clearance time but also the total evacuation time can be reduced. Simulation shows that Bee-Fire could save 10.12% clearance time and 15.41% total evacuation time; thus the congestion during the evacuation process could be effectively avoided and thus the evacuation becomes more systematic and efficient. [ABSTRACT FROM AUTHOR]

Governments in Australia and the UK see their duty to the public in the wake of the Grenfell Tower fire in simple terms of making buildings safe through cladding audits and bans on cladding products. But in the process they are largely ignoring the underlying issues that have led to the proliferation of Non-Conforming Building Products (NCBPs) and the even bigger problem of the non-compliant use of building products. By burdening strata/apartment owners with the costs of identification of suspect cladding as well as the costs of rectification, they have unfairly burdened the public and sent the wrong message about building compliance. This paper identifies a more equitable and effective approach to the immediate problem of combustible cladding and the wider problem of NCBPs and non-compliant building work. The paper discusses the need for all parties in the building supply chain to raise their game, how to avoid the incidence of substandard building products, and the need for professional associations to impose more stringent accreditation requirements on their members. Various regulatory and non-regulatory solutions are then proposed to help improve the building regulatory system. [ABSTRACT FROM AUTHOR]

Global population growth leads to a rapid urbanization of big cities and the development of transport infrastructure (airports, railway and bus stations). The strong urbanization in the cities of developing countries leads to a gradual rapprochement of dwellings and companies of airport zones. A fact that is real in Mali, where Bamako airport area has become an inhabited urban zone for some years by a part of the population. Given the importance of Bamako's airport traffic (West African crossroads), the proximity of the dwelling houses must receive the authorities and scientist's attention on the occupants' safety and quality life. The noise levels generated all around the airport zone throughout landings and take-offs by different aircraft types require an assessment of the acoustic noise level, the level of noise exposure and the building acoustic performance near the airport for users comfort and quality of life. In this article, we give in one hand the general notions on the inhabitants discomfort indicators, the building acoustics and, on the other hand, non-quality identification, and the discomfort factors whose resolution contributes to improving the building acoustic and environmental performance. These assessment studies are based on acoustic measurements and in-situ surveys from construction actors and users. Data from these surveys are processed with an evaluation methodology developed to improve knowledge and strategies aimed at preventing or minimizing the acoustic risks near airports. The capitalization of knowledge resulting from this study can serve as experience feedback through good practices advocacy and corrective and preventive solutions for building construction and renovation projects. [ABSTRACT FROM AUTHOR]

To create a safe work atmosphere, it is essential to control the spread of unsafe behaviors among construction workers. Based on group behavior theory, the relationship between the influence factors and means of spreading unsafe behavior among construction workers is verified using a structural equation model (SEM) and multiround research data. According to the research, (1) spreading methods of unsafe behaviors consists of demonstration-imitation and infecting-conformity; (2) the influence of important figures, personal safety accomplishments, intensity of penalties for individual violations and benefit-to-risk ratios of unsafe behaviors are correlated significantly with the spread of unsafe demonstration-imitation behaviors and (3) the relational closeness of members, personal safety accomplishments, safety climate and benefit-to-risk ratio of unsafe behaviors are correlated significantly with the spread of unsafe infecting-conformity behaviors. [ABSTRACT FROM AUTHOR]

A concrete type C20/25 was examined under biaxial dynamic compressive loading with several stress ratios and two different loading rates (75 and 150 1/s). The question to be answered is, if the two strength enhancing effects of biaxial compressive loading and elevated strain rate overlay under this combined loading condition. For these experiments a unique biaxial Split-Hopkinson-Pressure-Bar, developed at TechnischeUniversität Dresden, was used to load the cubic specimen with two compression pulses from two perpendicular directions, simultaneously. That means the pulses have to reach the specimen within a time span of maximum 25 μs to achieve a rising stress level in both spatial directions in the specimen. For comparison, further static uni- and biaxial trials, static-dynamic biaxial trials and dynamic uniaxial trials were conducted. After the trials, the particles of the fragmented specimens were analysed in size and shape. The results show clearly that the two examined strength increasing effects superimpose in case of a combined biaxial dynamic compressive loading, but not completely. Therefore the influence factor of each single effect was analysed, depending on the stress ratio and the strain rate. For the considered range of high loading velocities, the strain rate effect has the main influence on the strength enhancement. This effect is decreasing with a growing stress ratio, here the biaxiality gains more influence but still remains behind the strain rate effect. [ABSTRACT FROM AUTHOR]

Illegal building can take multiple forms, including squatter settlements and illegal building extensions. Among the various forms of illegal building, illegal microapartments (IMAs), which take the form of unauthorised subdivided housing units, have recently aroused wide public concern in Hong Kong. On account of their unlawful nature, IMAs pose serious threats to the safety of local communities by undermining structural stability and fire safety in buildings. They may also adversely affect natural lighting and ventilation for building occupants. Fatal fires in buildings with IMAs in recent years have demonstrated the painful consequence of ignoring this issue in the city. Nonetheless, the problem of IMAs has seldom attracted scholarly attention around the world. In light of the seriousness of the IMA problem in Hong Kong, this study explores workable policy options for cracking down on the problem. It reviews policies or proposals in different jurisdictions to crack down on IMAs. Then a threeround policy Delphi study is carried out with a panel of stakeholders to identify and prioritise policy options for combating IMAs in Hong Kong. Various measures are proposed or identified by the panel members, ranging from increasing the frequency of building inspections and imposing stricter penalties on non-conforming owners to licensing IMAs for private renting. Among these options, stricter enforcement is considered the most workable option. The results of the policy Delphi study are discussed and policy recommendations are made. [ABSTRACT FROM AUTHOR]

Fire disaster happens to be one of the world’s most common and destructive disasters. It has over the years been a disturbing issue to handle most especially in developing countries. This study aimed at evaluating fire safety measures in the design and construction of high-rise buildings in Nigeria. The importance of this study is the evaluation of fire safety measures towards enhancing the safety of occupants and properties. The study consisted of a case study survey and questionnaire administration among the building occupants. The occupant survey is to determine their perceptions of fire safety measures in high-rise buildings and the practicability of measures that could be adopted to improve safety. From the occupant survey, 88% of the respondents have awareness on fire safety measures in buildings. The results also indicated that the most common causes of fire incidences in high-rise buildings are an electrical fault. This could be avoided where electrical conduits and fittings are properly installed and monitored. The results further revealed the need to improve on fire safety measures undertaken by both designers and property owners. A careful observance of fire safety measures as specified in building codes must be considered in the design of high-rise buildings. [ABSTRACT FROM AUTHOR]

Tracking modal parameters and estimating the current structural state of a building from seismic response measurements, particularly during strong earthquake excitations, can provide useful information for building safety assessment and the adaptive control of a structure. Therefore, online or recursive identification techniques need to be developed and implemented for building seismic response monitoring. This paper develops and examines different methods to track modal parameters from building seismic response data. The methods include recursive data-driven subspace identification (RSI-DATA) using Givens rotation algorithm, and RSI-DATA using Bona fide algorithm. The question on how well the results of RSI-DATA reflect the real condition is investigated and verified with a bilinear SDOF simulation study. Time-varying modal parameters of a four-story reinforced concrete school building are identified based on a series of earthquake excitations, including several seismic events, large and small. Discussions on the different methods' ability to track the time-varying modal parameters are presented. The variation of the identified building modal frequencies and damping ratios from a series of event-by-event seismic responses, particularly before and after retrofitting of the building is also discussed. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A toxic gas release, e.g. H2S, from pipeline accidents or sour wells, although improbable, may lead to serious consequences for the health of people and the environment. Such incidents might also jeopardize occupants of nearby indoor environments via infiltration of toxic contaminants. Despite that risk, there is still a lack of data and of comparative studies concerning the appropriate models and mitigation methods. The purpose of this work is, therefore, the improved modelling of toxic gas building infiltration, by a combination of tools and approaches. Using a realistic release scenario, the present comprehensive analysis demonstrates the need to consider the detailed building characteristics and meteorology. Significant deviations are observed between simple and advanced building ingress models. Furthermore, the consequences assessment leads to contradicting conclusions depending on the employed dose-response approaches. The proposed methodology could serve as a guide for the improvement of relevant risk-assessment tools and of future studies. [ABSTRACT FROM AUTHOR]

The article discusses the importance of building codes in protecting safety and health of residents in New York City. It refers to the regulation of construction operations which is crucial in densely populated areas. It notes that building codes aims to protect the safety and health of residents by regulating the finished building products.

One of the most critical stages for a structure's safety is its construction process, and this problem is even more acute in buildings with reinforced concrete structures. These structures are usually built by shoring successive floors, so that the most recently poured floor rests on the lower floors by means of shores. It is therefore vitally important to have calculation tools available to estimate the loads to which the shores and slabs will be subjected in each stage of construction. A number of calculation methods have been proposed to date, of which the one proposed by Grundy and Kabaila in 1963 is the best known and most frequently used. This paper analyzes the limitations of Grundy and Kabaila's method by means of a parametric study of finite-element method simulations that identified a large number of situations in which this method presented unsafe results in terms of the estimated loads on slabs. In many situations, therefore, applying this method could gravely affect a building's in-service behavior and durability. The paper's final objectives are to make the reader aware of the limitations of Grundy and Kabaila's method and the need to use the more refined methods that are now available to estimate the loads on shores and slabs in reinforced concrete buildings under construction. [ABSTRACT FROM AUTHOR]

Since tracking modal parameters and estimating the structural current state from building seismic response measurement can provide useful information for building safety assessment, online or recursive identification techniques need to be developed and implemented on building seismic response monitoring. In this article, two recursive subspace identification algorithms are developed. One is the recursive subspace identification with BonaFide LQ renewing algorithm (recursive subspace identification BonaFide) incorporated with moving window technique to identify modal parameters at each time instant during the earthquake excitation. Besides, recursive subspace identification based on matrix inversion lemma algorithm (recursive subspace identification Inversion) is also used and keeps the same data window with recursive subspace identification BonaFide only for the initial identification and then appends the following data points to identify modal parameters for the whole excitation time history. A forgetting factor is introduced to emphasize the latest state of system in this method. Two different sets of building seismic response data are used to verify the applicability of the proposed methods. One is the three-story steel structure with abrupt change of story stiffness shaking table test in laboratory, the other is a series of seismic response of a four-story-reinforced concrete elementary school building, including several large seismic events. It is concluded that both methods can detect the time when the floor stiffness was changed but recursive subspace identification Inversion with forgetting factor can provide more accurate estimation of the change of stiffness. [ABSTRACT FROM AUTHOR]

Due to the increase of the frequency and severity of hydrik risk phenomena, applying GIS techniques for spatial analysis became indispensable for the identification of the most vulnerable areas to floods and flash-floods. In this study, a proper methodology was used to estimate built areas vulnerability to flash-floods within Pănătău river basin, which is located in a very exposed area. Thus, the buildings vulnerability index (BVI) was defined and calculated by including the following components: the Flash Flood Potential Index (FFPI) and the buildings density within the built-up area (D). The calculation of BVI was based on multiplying the standardized values of these two components. The results highlighted a high and very high vulnerability to flash-floods, on almost 13% of the total area. According to the spatial distribution of BVI values, within each village, the most vulnerable surfaces are located in Pănătău and Sibiciul de Jos, which is also attested by data from the National Romanian Water Administration. On the other side, Lacu cu Anini village is the less vulnerable. [ABSTRACT FROM AUTHOR]

Every country is dealing with its own housing problems; however, none compares with Hong Kong where housing has always been a major concern as a result of low supply over the past decades. Against the constraints in delivering sufficient houses, prefabrication as a sustainable solution for housing has been increasingly advocated for its potential merits of better quality, construction safety and cleaner built environment. However, schedule delay caused by various risks affected the prefabrication housing production (PHP) in Hong Kong. This problem can be further worsened when the manufacturing sector of PHP has entirely moved to offshore areas in the Pearl River Delta region. This study applies system dynamics to recognize and investigate the potential effect of various risks on the scheduling of prefabrication housing construction projects through the employment of Vensim software package. The simulation results show that schedule risks, namely low information interoperability between different enterprise resource planning systems (LIIBDERPS), logistics information inconsistency due to human errors probability (LIIHEP), Delay of delivery of precast element to site (DDPES), and Design information gap between designer and manufacturer (DIGDM) significantly contribute to the schedule delay in PHP. However, schedule is more sensitive toward LIIBDERPS than for the other three risks, indicating that LIIBDERPS should be monitored and given priority. The system dynamic model serves as an effective tool for quantitatively evaluating the effect of various risks on the schedule of PHP, offering valuable references for managers though comparing simulation results under different risk scenarios, so that potential risks that might lead to schedule delay could be identified and handled in advance. [ABSTRACT FROM AUTHOR]

Construction still accounts for a disproportionate number of injuries, inducing consequent socioeconomic impacts. Despite recent attempts to improve construction safety by harnessing emerging technologies and intelligent systems, most frameworks still consider tasks and activities in isolation and use secondary, aggregated, or subjective data that prevent their widespread adoption. To address these limitations, we used a newly introduced conceptual framework and accompanying natural language processing system to extract standard information in the form of fundamental attributes from a set of 5298 raw accident reports. We then applied state-of-the-art data mining techniques to discover attribute combinations that contribute to injuries. We refer to these incompatibilities as “construction safety clashes”. The main contribution of our study lies in the methodological advancements that it brings to the construction safety domain. In light of the results obtained, our approach shows great promise to become a standard way of extracting valuable, actionable insights from injury reports in a fully unsupervised way. The use of our methodology could enable construction practitioners to ground their safety-related decisions on objective, empirical data, rather than on limited personal experience or expert opinion, which is the current industry standard. Finally, our methodology allows construction accidents to be viewed as perturbations in underlying networks of fundamental attributes. While the analysis of the current data set provides preliminary evidence for this theory, comparison to non-accident reports will be required for validation. [ABSTRACT FROM AUTHOR]

Improvement of safety and productivity are major concerns throughout the construction industry. There is a dearth of efforts that document the need for simultaneous achievement of safety and productivity on construction sites. The objective of this research is to investigate productivity and safety simultaneously on construction projects by conducting a survey. In total, 1,800 hard-copy questionnaires were distributed and the response rate was 81%, resulting in 1,454 valid questionnaires for analysis. Safety and productivity were investigated on 25 construction projects by means of statistical analysis. The results indicated that eleven of the fifteen significant findings pertained to safety and the rest to productivity. The results confirmed that it is possible to improve productivity and safety simultaneously on construction projects. All measures were found to be correlated with both safety and productivity. The findings of this research provide practical knowledge to project managers and safety practitioners on construction projects to achieve safety and productivity simultaneously. The methodology of research might be useful for research at other construction projects in other regions and cultures. [ABSTRACT FROM PUBLISHER]

It should be pointed out that salt crystallisation and rising dampness are two separate but interconnected processes. Both of these damages must be understood if damage is to be minimized and if corrective measures are to be successful. However, the term rising damp has been usually used to cover both aspects, it tends to overlook the role of salt, and issues that will increasingly significant due to the buildings are getting older and as the soils are becoming more saline. Hence this paper will focus on background and an understanding of salt crystallisation and rising damp problems. Furthermore, the discussion also will include the indications, causes and effects of both damages. [ABSTRACT FROM AUTHOR]

In this paper a robust model has been developed to predict the average bond stress-slip relationship between the strands and concrete of prestressed concrete structural members. Two bond-slip curves have been proposed to represent the bond-slip characteristics for the three-wire and seven-wire strands. This model considers the variation of concrete properties, strands’ geometries and the type of strand surface, smooth or indented. The degradation of materials and bond characteristic at elevated temperatures are also included in the model. The proposed model has been validated against previous experimental results at both ambient and elevated temperatures. [ABSTRACT FROM AUTHOR]

Antiram bollard systems (ABSs) can effectively prevent vehicle bombs from approaching protected buildings and infrastructures and thus reduce the damage from blast and debris. This paper presents an assessment of existing models for predicting the maximum impact force of truck frontal crashing into ABS. Four available tests and 63 numerical experiments were assembled for the evaluation. Assessment results show that the design model in one design code is of the highest accuracy, while other existing models present worse predictions. However, the design model in the best-performing code is unreasonable since the energy absorbed by the deformation of ABS was not considered. Numerical investigation shows approximately 81% of the initial kinetic energy is transformed into the strain energies of truck, impacted bollard, and foundation during the crash. On this basis, a new maximum impact force model was proposed. The comparisons between the model predictions and the experimental results from tests and numerical simulations indicate that the proposed model is more accurate and rational than the existing models. [ABSTRACT FROM AUTHOR]

Lightning is a natural occurring phenomenon having a very high voltage and current. Building protection from the effect of lightning stroke is one of the most important features. Lightning flash, nature changes with increasing the clearance between the ground structure and the cloud. Providing proper protection to the building, Frankling rod/Lightning air terminal is an essential element to receive the lightning flashes in order to make sure the protection of building. In this paper a down scaled building with four lightning rods has been chosen to see how the lightning rods with different air gap and view of the building perform, in lightning flash. The building is tested with three different views which are front, back and side views. The lightning rods provided different air gaps/clearance between the plain and the top plate. Single stage impulse generator is used. A voltage up to 90 kV is applied to analyze the lightning flash receiving ability of lightning rods. Through experimental work the lightning flash receiving ability is studied in detail for three views of the down scaled building. [ABSTRACT FROM AUTHOR]

The article presents a mode of functioning of an application which generates two check-up sets. These sets are then used for detecting and localizing the faults of the elements of complex technical objects. The article presents general algorithms for building check-up sets used for the diagnosis of the object's technical state. It takes place in two steps within which the current evaluations of the tested features that belong to both of the mentioned sets are compared with the values included in the individual matrix rows of the fault model of this object. In the article there are shown examples of generating check-up sets for the case when the object's examined features were evaluated in a two- or three-valued way. [ABSTRACT FROM AUTHOR]

This analysis develops a Basic Model focusing on the loss of productive time resulting from death or injury as of prime importance in measuring trends in the safety environment supplemented by a Financial Model measuring loss in dollar terms. This provides two views of the impact of death and injury in the construction industry in the 41 states for which comparable fatality and injury data were available for the period 2003 through 2012. This period is significant in that it includes periods of boom, bust and recovery. In undertaking this study we developed a state-by-state measure of lost work-life expectancy due to fatalities. Traditional approaches to costing have tended to focus on medical costs, workers’ compensation employment cost and other cost elements as well as victim productivity. In this analysis the impact of death and injury on the individuals involved is the focus with other factors treated as secondary. Applying the Basic and Financial Models to the 2003–2012 period results in findings showing notable improvement in construction safety. [ABSTRACT FROM AUTHOR]

This paper presents an innovative approach of integrating Building Information Modeling (BIM) and expert systems to address deficiencies in traditional safety risk identification process in tunnel construction. A BIM-based Risk Identification Expert System (B-RIES) composed of three main built-in subsystems: BIM extraction, knowledge base management, and risk identification subsystems, is proposed. The engineering parameter information related to risk factors is first extracted from BIM of a specific project where the Industry Foundation Classes (IFC) standard plays a bridge role between the BIM data and tunnel construction safety risks. An integrated knowledge base, consisting of fact base, rule base and case base, is then established to systematize the fragmented explicit and tacit knowledge. Finally, a hybrid inference approach, with case-based reasoning and rule-based reasoning combined, is developed to improve the flexibility and comprehensiveness of the system reasoning capacity. B-RIES is used to overcome low-efficiency in traditional information extraction, reduce the dependence on domain experts, and facilitate knowledge sharing and communication among dispersed clients and domain experts. The identification of a safety hazard regarding the water gushing in one metro station of China is presented in a case study. The results demonstrate the feasibility of B-RIES and its application effectiveness. [ABSTRACT FROM PUBLISHER]

Construction four-dimensional (4D) models have emerged to become a powerful tool for effective construction planning and control. However, the emphasis has been visualization and 4D topological analysis capabilities are not well-incorporated in the existing practice. Some 4D models enabled space-time conflict detection or site layout analysis, subtypes of 4D topological analysis; these functions are fragmented and constrained in particular construction scenarios. This paper presents a generic construction 4D topology framework that enables 4D topological analysis to support a wide range of construction planning tasks. The framework includes a 4D topological representation method that formalizes the spatial-temporal relationships between construction activities, a topology categorization method that formats the 4D topological representations into task templates, and a mathematical method to conduct the analysis. The framework is tested in a prototype through a case study, which proves that the framework is able to facilitate many construction planning works such as space-time conflict detection and test for crane's cover range. [ABSTRACT FROM AUTHOR]

• Study on the adhesion strength of rock-concrete interface by PFC3D. • Derive the interface stiffness equation combined interface mechanics. • Modify the flat-joint model to simulate the interface of rock-concrete. • The propagation process of interface plane crack is analyzed. • The numerical model can accurately estimate the interface adhesion strength. In tunnel engineering constructed by NATM, the adhesion strength between surrounding rock and lining is an important index to measure the safety of tunnel construction. However, the field measurement and laboratory test inevitably have the problem of low efficiency. In contrast, reasonable numerical simulation can be an alternative way to study rock-concrete adhesion strength. Therefore, in this paper, the influence factors of the adhesion strength of rock-concrete are studied by direct tensile laboratory test combined with particle flow code in three-dimension (PFC3D). The flat-joint model was used to reproduce the behavior of rock and concrete. The concept of effective elastic modulus of bi-material interface was introduced to derive the modified equation of interface normal stiffness. Then the modified flat-joint model was applied to PFC3D based on the Fish language and the interface parameters were calibrated. Compared with the results of laboratory tests, it is found that this method can accurately simulate the adhesion strength between rock and concrete, which can also restore the post-peak response of laboratory tests. Therefore, more parameter studies are considered which show that: the mechanical properties of rock have little influence on the adhesion strength of composite specimens. However, the physical properties of rock, such as porosity, have great influence on that, which can be seen from the crack propagation mode at the interface of composite specimens. Sandstone cemented better with concrete will retain the rate sensitivity of rock and concrete materials to the greatest extent. When the experimental strain rate increases from 0.06 s−1 to 0.9 s−1, the adhesion strength of sandstone-concrete specimens increases by 50 %, while that of granite-concrete specimens hardly changes. The research results can be helpful to better understand the adhesion performance of rock-concrete interface and have certain engineering significance for tunnel construction supported by shotcrete. [ABSTRACT FROM AUTHOR]