China Architecture Design & Research Group (China)

Summary This study assesses the seismic performance of a hybrid coupled wall (HCW) system with replaceable steel coupling beams (RSCBs) at four intensities of ground motion shaking. The performance of the HCW system is benchmarked against the traditional reinforced concrete coupled wall (RCW). Nonlinear numerical models are developed in OpenSees for a representative wall elevation in a prototype 11‐story building designed per modern Chinese codes. Performance is assessed via nonlinear dynamic analysis. The results indicate that both systems can adequately meet code defined objectives in terms of global and component behavior. Behavior of the two systems is consistent under service level earthquakes, whereas under more extreme events, the HCW system illustrates enhanced performance over the RCW system resulting in peak interstory drifts up to 31% lower in the HCW than the RCW. Larger drifts in the RCW are because of reduced coupling action induced by stiffness degradation of RC coupling beams, whereas the stable hysteretic responses and overstrength of RSCBs benefit post‐yield behavior of the HCW. Under extreme events, the maximum beam rotations of the RSCBs are up to 42% smaller than those of the RC coupling beams. Moderate to severe damage is expected in the RC coupling beams, whereas the RSCBs sustain damage to the slab above the beam and possible web buckling of shear links. The assessment illustrates the benefits of the HCW with RSCBs over the RCW system, because of easy replacement of the shear links as opposed to costly and time‐consuming repairs of RC coupling beams. Copyright © 2016 John Wiley & Sons, Ltd.

Abstract On June 24, 2021, a 40-year-old reinforced concrete flat plate structure building in Miami suffered a sudden partial collapse. This study analyzed the overall performance and key components of the collapsed building based on the building design codes (ACI-318 and GB 50010). Punching shear and post-punching performances of typical slab-column joints are also studied through the refined finite element analysis. The collapse process was simulated and visualized using a physics engine. By way of these analyses, weak design points of the collapsed building are highlighted. The differences between the reinforcement detailing of the collapsed building and the requirements of the current Chinese code are discussed, together with a comparison of the punching shear and post-punching performances. The simulated collapse procedure and debris distribution are compared with the actual collapse scenes.

We present unprecedented datasets of current and future projected weather files for building simulations in 15 major cities distributed across 10 climate zones worldwide. The datasets include ambient air temperature, relative humidity, atmospheric pressure, direct and diffuse solar irradiance, and wind speed at hourly resolution, which are essential climate elements needed to undertake building simulations. The datasets contain typical and extreme weather years in the EnergyPlus weather file (EPW) format and multiyear projections in comma-separated value (CSV) format for three periods: historical (2001-2020), future mid-term (2041-2060), and future long-term (2081-2100). The datasets were generated from projections of one regional climate model, which were bias-corrected using multiyear observational data for each city. The methodology used makes the datasets among the first to incorporate complex changes in the future climate for the frequency, duration, and magnitude of extreme temperatures. These datasets, created within the IEA EBC Annex 80 "Resilient Cooling for Buildings", are ready to be used for different types of building adaptation and resilience studies to climate change and heatwaves.

The welded truss composed of circular hollow section (CHS) braces and concrete-filled circular hollow-section (CFCHS) chords is a new kind of structural system that has been increasingly applied in large span arch bridges in China. It is necessary to have a good knowledge of fatigue strength of the welded CHS-to-CFCHS joints for the design of this kind of composite bridge. This paper reports on a series of tests on welded CHS-to-CFCHS T-joints subjected to axial cyclic fatigue loading in the brace. Eleven joints were designed to investigate various influence factors such as different nondimensional geometric parameters of circular hollow sections and different concrete strength grades. The quality of welds connecting brace and chord members were examined using the magnetic particle and radiographic inspection methods. The conditions of hot spot stress at both the crown and saddle positions in brace and chord members were determined by means of linear and nonlinear extrapolation methods. During the fatigue testing process, the number of cycles relating to several stages of failure, the crack initiation positions, crack propagation patterns, and the final failure modes were recorded. Fatigue strength of the CHS-to-CFCHS T-joints was compared with that of CHS-to-CHS T-joints. It is concluded that the CHS-to-CFCHS T-joints have a much lower stress concentration factor and consequently have better fatigue strength than the CHS-to-CHS T-joints, when both kinds of joints have the same nondimensional geometrical parameters and same nominal stresses on the brace. The Srhs-Nf curves in the Comité International pour le Développement et l’Étude de la Construction Tubulaire guidelines used for CHS-to-CHS joints are not appropriate for the reliable fatigue assessment of CHS-to-CFCHS T-joints based on the current test data.

Tourism has been seen and adopted as a vital means for achieving rural economic and social revitalization worldwide without harming sustainable development principles. For China, the evaluation of rural tourism competitiveness at the township level is essential for planning and developing the tourism industry as a basic administration and economic unit, but there is not enough research due to the lack of applicable data and systematic methods. Therefore, this study constructed a town-level rural tourism competitiveness evaluation and development mode classification model based on the modified Michael Porter’s Diamond Model using integrated multi-source data. By taking the 1806 township units in Henan Province, China as examples, we conclude four different modes based on the level of the comprehensive score and industrial internal balance (i.e., balanced development mode with multiple advantages, related and supporting industries driving mode, ecological resource-led mode, and rural landscape experience mode). Policy suggestions for the optimization of the rural tourism industry for Henan are discussed based on the results.

Current design manuals for fiber-reinforced polymer (FRP) structures only allow limited application of FRP in high-temperature environments. However, the residual mechanical properties of FRP composites at high service temperatures should be considered. This paper presents the results of bending tests on FRP coupon specimens at temperatures from 25 to 120°C and of compression tests on FRP components at temperatures from −40 to 90°C. Although the mechanical properties decrease with increasing temperature, they retain residual strength and stiffness at high service temperatures. The influence of subzero temperatures on the mechanical properties is negligible. Additionally, the flexural properties of the coupon specimens and the compressive properties of the components were experimentally investigated after high-normal temperature cycles, which alternated between 45 and 135°C every 12 h. The results show that repeated high-normal temperature cycles have little effect on the mechanical properties. The simultaneous effects of loading and high-temperature environments on FRP structures should be considered during design. Thus, this paper proposes a design method for calculating the loading capacity of FRP members at different temperatures. Experimental data from literature and this study were normalized and compared with the results predicted by this method. As expected, the proposed method provides a lower envelope of experimental data for both strength and modulus. Thus, the design method can conservatively estimate various mechanical properties of FRP structural members under different loading conditions at high service temperatures. Additionally, the method can be conveniently established and applied in design.

Informal learning spaces play a significant role in enriching student experiences in learning environments. Such spaces are becoming more common, resulting in a change to the spatial configuration of built environments in higher education. However, previous research lacks methods to evaluate the influence of the spatial design characteristics of informal learning spaces on student preferences and their activities within. This paper aims to tease out the spatial design characteristics of informal learning spaces to examine how they shape students’ preferences in terms of their use of the spaces and what they do within them. The two case studies selected for this study, both in the UK, are the Diamond at the University of Sheffield, and the Newton at Nottingham Trent University. A mixed-methods study is applied, including questionnaires, observation, interviews, and focus groups. Six significant design characteristics (comfort, flexibility, functionality, spatial hierarchy, openness, and other support facilities) that influence student use of informal learning environments are identified. These can be used to inform future design strategies for other informal learning spaces in higher education.

Focusing on the multiple objectives of maximum solar heating capacity, maximum COP of heat pump and minimum soil heating capacity, a model of one typical building and two heating strategies was established in the TRNSYS. Non-dominated Sorting Genetic Algorithm (NSGA) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) based on entropy weight are used to optimize operation parameters. Optimized control strategies and equipment parameters of a combined geothermal and solar system in cold and arid regions were taken as the research objects. The final optimized strategy and the original strategy of the single ground source heat pump heating system were compared. Research results show that the optimized control strategy of the geothermal solar heating system transforms solar hot water from the storage tank to heating terminals in the heating season and transforms solar hot water to the ground heat exchanger in the non-heating season. Compared to GSHP, the optimizing strategy saves 16.8 MWh annually, and the energy saving rate is 20.59%. Soil temperature drop increases from 2.74 °C to 0 °C. The annual electricity saving cost intensity is about 4 yuan/m2, and the CO2 emission reduction intensity is 4.3 kg CO2/m2. This study provides a solution for soil temperature reduction in one year and low-cost operation in cold and arid regions during ground source heat pump applications.

Based on identification and prediction ability of neural networks for nonlinear systems, an improved BP network was adopted to predict the seismic responses of the bridge structures. First, a multi-player BP networks based on Levenberg-Marquardt algorithm was formed. Then, the improved neural network was trained by the imitated seismic responses of the first 4 seconds which were obtained from artificial earthquake waves by finite element method. Thirdly, the seismic responses of 1st to 8th seconds for the same bridge structure were predicted use the neural network which has been trained, and the predict responses were compared with the calculation data. The error curves between the prediction and the calculation results show that the BP network combined with is Levenberg-Marquardt algorithm has very good convergence rate, and the artificial neural network can predict the dynamic response of bridge structures well enough.

Vibration isolators are widely used to mitigate undesirable vibrations in engineering systems and structures, but low-frequency vibration isolation remains a challenge. Origami-inspired structures, with their tunable stiffness and transformative capabilities, offer potential for vibration isolation . Inspired by conical Kresling origami, this study proposes a quasi-zero-stiffness vibration isolation system. Static analysis of the origami structure reveals that the system exhibits near-zero dynamic stiffness at the static equilibrium position , while maintaining static stiffness during the load-bearing process. The amplitude-frequency characteristic formula and vibration transmissibility formula are derived using the harmonic balance method. The effects of varying damping ratios and excitation amplitudes on the amplitude-frequency and transmissibility curves are examined. It is shown that the vibration isolation range increases with the number of layers. A comparison of the system's response to harmonic vibrations under different compressive deformations highlights the effectiveness of the origami quasi-zero-stiffness system as a vibration attenuator . Compared to existing quasi-zero-stiffness dampers, the origami-inspired system features a wider isolation frequency band, a lower initial isolation frequency, and reduced vibration transmissibility, demonstrating superior isolation performance, particularly at low frequencies.

It has been well accepted that performance-based seismic design (PBSD) principles and procedures will be at the core of the next generation of seismic design codes. PBSD necessitates the quantitative assessment of seismic damage suffered by structures. Quantitative assessment of damage has been proved effective in controlling the earthquakeinduced damage of structures, and is feasible by the use of damage models. So far the Park-Ang damage model has remained to be the most widely used one. This model, however, has the inherent deficiency referring to its convergence at upper and lower limits. In this study, a modification is proposed for the original Park-Ang damage model, eliminating its non-convergence problem at upper and lower limits. The combination coefficient of the modified model is calculated using the cyclic test results of flexure-dominant RC members from the database provided by the Pacific Earthquake Engineering Research Center and the author's own tests. An empirical formula is derived through multivariable nonlinear regression analysis to relate the coefficient with three design parameters. The comparison between the modified and original model indicates that the damage index of flexure-dominant RC members can be determined by the modified model with higher precision and smaller scatter. The damage indices at principal damage states are calculated by the modified damage model for each member in the above mentioned database. Accordingly, the performance levels of RC structural members are quantified by setting the individual limit value of damage index.

This paper presents a study on dynamic characteristics and seismic responses of traditional Chinese timber-frame structures. Micro-tremor measurements were conducted to obtain natural frequencies, vibration modes, and damping ratios. A three-dimensional numerical model considering unique connections, the mass of roof and wooden floor, and adobe walls was developed by ANSYS software and calibrated with the data from prior on-site test. Seismic responses including time histories responses, inter-structural layer drift angles, and isolation characteristics were further discussed. Results indicate that both mortise-tenon joints and the Dougong brackets play an essential role in the vibration isolation and strong lateral force resistance. Also, Dougong fully deforms under the major earthquakes, thereby dissipating more seismic energy. The lateral stiffness of column-beam frame is lower than that of the roof truss. The seismic abilities of the whole structure under the Lanzhou wave are smaller than those under the El Centro wave and the Taft wave.

The aerodynamic instability critical wind velocity of three-dimensional membrane structures is studied by combining the non-moment theory of thin shallow shells and the potential flow theory in fluids. The dynamic equilibrium equation of the structure is established by applying the non-moment theory of thin shells, with the assumption that the coming flow is uniform ideal potential flow. The aerodynamic interaction equations of the membrane structure in two cases, i.e., the wind is in the structural arch or sag direction, are obtained based on the aerodynamic forces being determined by applying the potential flow theory and the thin airfoils theory in which the wind-structure interaction is taken into account. Bubnov-Galerkin approximate method is applied to transform the interaction equation into a second order linear ordinary differential equation; and the instability critical wind velocity is obtained from Routh-Hurwitz stability criterion.

In the past 40 years, China has undergone a rapid urbanization process which has led to a significant contradiction between the desire to develop modern urban spaces and the need to protect historic urban sites. Urban construction has brought not only the destruction of the physical space of the historic urban sites, but also the fragmentation of the natural landscape and its structural disconnection to the historic urban landscape. Ancient Chinese planners had their own thoughts regarding urban construction and the specific patterns of the urban landscape. The urban landscape of Chinese historic cities focuses predominantly on the structural relationship to its neighborhood. This paper aims to explore the value and character of the historic landscape of the ancient city, finding the key causes of its decline in the process of urbanization. The World Cultural Heritage city Pingyao is taken as a case study. Firstly, an analysis of its historical spatial structure and urban planning ideas of the ancient city of Pingyao using ancient maps and historical documents is presented. Then, a quantitative analysis of the urban space expansion in Pingyao city from 1989 to 2016 is conducted and its land use structure further analyzed. Additionally, four editions of the urban master plan in Pingyao have comprehensively shown that modern urban construction and planning tend to focus more on urban economic functions and social needs. In contrast, ancient urban planning relied on the spatial connection between urban space and its natural environment to construct a higher urban cultural connotation. As a result, the different development mode between modern urbanization and construction of ancient cities could be the key reason for the decline of spatial structure and landscape fragmentation of historical cities in China. With respect to the experience and thoughts of Pingyao’s ancient urban planning and construction, technical ideas and suggestions are put forward as reference in future spatial planning for Pingyao’s urban development and cultural protection. Our findings have been incorporated into the relevant sections of the spatial planning of Pingyao.

Summary The frame‐core tube‐outrigger structural system is widely used in tall buildings, in which outriggers coordinate the deformation between the core tube and the moment frame, leading to a larger structural lateral stiffness. Existing studies indicate that outriggers can be designed as “fuses” of tall buildings through dissipating seismic energy after yielding, to protect the main structure. To date, both conventional and buckling‐restrained brace (BRB) outriggers have been applied in practice. Subjected to the maximum considered earthquake (MCE), the hardening effect of BRB outriggers increases the damage of other structural components. Meanwhile, conventional outriggers are difficult to repair, owing to the local buckling‐induced severe deterioration and damage. To overcome these problems, this study proposes a novel sacrificial‐energy dissipation outrigger (SEDO) to improve the seismic resilience of tall buildings. The chords of SEDO are made of high‐strength steel and remain elastic. The inclined braces of the SEDO are composed of a sacrificial part and an energy‐dissipating part. Therefore, the SEDO remains elastic under design‐based earthquakes (DBEs) and dissipates inelastic energy under MCEs. Moreover, the detailing of this novel SEDO is proposed on the basis of experimental studies. The optimal strength ratio between the sacrificial part and the energy‐dissipating part is determined in the range of 6:4 to 4:6 on the basis of nonlinear time history analyses (THAs) and parametric studies. Afterwards, the SEDOs are used in an actual tall building to verify their seismic performances through nonlinear THAs. The results indicate the proposed SEDO is able to protect other structural components and effectively improve the seismic resilience of tall buildings.

Serious games, as an engaging medium on energy consumption, have recently become more popular, as they present an educational mechanism to engage end-users. A novel application of serious games in engaging and educating end-users has been validated during the last years. However, there is little research focusing on the review of its development trends, categories and approaches. The proposed paper reviews serious games as an engaging medium for building energy consumption. The research focuses on the role of energy-consumption awareness-related education in motivating end-users to save energy and make informed decisions to change energy-related behaviours. This research stresses the approaches to underlining the issue as ascertained from a number of efficiency-related serious games. The investigation suggests the potential impact that serious games can have on changing the domestic practices of householders, in a safe, fun and interactive environment. This would enable householders to investigate alternative ways of meeting energy-consumption targets and realise the limits to their energy-saving potential. It concludes that at present, serious games do not take advantage of the opportunities available in energy monitoring and sub-metering, or real-life energy behaviours. Meanwhile, the existing evaluation framework for the effectiveness of an energy serious game still needs to be further developed. However, active engagement in energy monitoring has contributed to numerous past successes in energy use reduction, and gamification and serious games show great potential for building upon these achievements.

Most previous studies on urban vitality focused on the analysis and evaluation of the overall vitality of urban agglomerations or single cities, while there are few related studies at the micro scale, such as subdistricts and even blocks. Based on multisource data and using the kernel density analysis and entropy methods, the economic vitality, social vitality, cultural vitality, ecological vitality and comprehensive vitality of each subdistrict in Shanghai were measured. Additionally, correlation analysis, the ordinary least squares (OLS) regression model, the spatial lag model (SLM) and the spatial error model (SEM) were used for fitting analysis to reveal the influencing mechanism of urban subdistrict vitality. The results showed that (1) the spatial distribution of economic vitality and social vitality in Shanghai showed the spatial characteristics of radiating outward from the center, and the types of social activity location corresponding to different levels of hotspot areas are different. Cultural vitality showed the spatial distribution characteristics of “gathering in the centre and dispersing around, with Puxi higher than Pudong”, but the cultural vitality values of different subdistricts vary greatly. Ecological vitality showed an increasing trend from the center to the surrounding areas. (2) The overall urban vitality of Shanghai also showed a decreasing circular structure from the center to the periphery. (3) Among the three regression models, i.e., the OLS regression model, SLM and SEM, the model with the best explanation of urban vitality is the SLM, which had an R2 of 0.6984, indicating that it can explain 69.84% of the spatial distribution pattern of urban vitality. (4) The factors that have significant effects on urban vitality are functional mix, metro station accessibility, metro station density, bus station density and intersection density, and all of them are positively correlated. The order of the strength of the effects is bus station density > metro station density > intersection density > metro station accessibility > functional mix.

Unloading of foundation pit excavation will no doubt induce the soil deformation and have result in uneven settlements of adjacent metro tunnels.The excessive settlements may induce the crack of tunnel segments and eventually may affect the safety use of metro trains.Two-stage method is presented for determining the longitudinal deformation of metro tunnels caused by adjacent foundation pit excavation.The soil unloading effects of the bottom plan and the surrounding walls induced by the foundation pit excavation can be considered by this method.Firstly the additional stress due to adjacent foundation pit excavation is calculated.Secondly the governing differential equation is built up based on Winkler model.Then the differential equation is deduced to the finite element equation by the Galerkin method;and vertical displacement and internal forces along longitudinal axis are obtained.Furthermore,the parametric analysis of existing tunnels is carried out;such as,the different depths,the distance from the excavation site,the different geologic conditions and the different outer diameter of the tunnel.Finally,the results from present approach are compared with that from 3D numerical simulation and measured data;good agreement is obtained.It may provide certain basis to draw up correctly protective measures of metro tunnels influenced by adjacent excavation.

The radiant heating system assisted by an air source heat pump has been widely applied in China for its effective energy conservation, high comfort performance and flexible utilization. Because the coefficient of performance of the system is strictly controlled by the supply water temperature heated by the air source heat pump, an efficient radiant terminal with low-temperature supply water is of significance to the coefficient of performance. In this research, the energy-saving feature of the capillary mat radiant heating system was first proved theoretically based on the influence of the heat transfer temperature difference on the coefficient of performance of the air source heat pump. In order to compare the performances of the capillary mat radiant and floor radiant heating systems, an experiment platform of two different radiant terminals assisted by an air source heat pump was established in a residential building in Xi’an, China. Experimental results showed that, to satisfy the indoor heating requirements, the supply and return water temperatures ought to be 35.0℃ and 30.9℃, respectively, and for the capillary mat radiant heating system, 43.9℃ and 38.8℃, respectively, for the floor radiant heating system. However, the electricity consumption of the capillary mat radiant heating system is 45% less than that of the floor radiant heating system. Thus, our study validated the energy-saving potential of the capillary mat radiant heating system assisted by an air source heat pump.

A preliminary Indoor Air Quality study was performed in 26 residential homes in 6 cities in different climate zones in China. In Chinese urban environments, coal gas and natural gas are used as the main fuels for cooking. Analysis of the results employed the ratio of living room to kitchen (L/K) pollutant concentrations and the correlation of their levels to assess the transport of pollutants indoors. Sources in the kitchen affect living room concentrations of SO 2 , NO, NO 2 , and CO, less so that of CO 2 levels and weakly of PM 10 . Among all the pollutants, SO 2 has the minimum 0.88 L/K ratio value, and maximum correlation value, R2=0.89; on the other hand, PM 10 has the maximum L/K ratio value, 1.20 and minimum R 2 -value, 0.55, which means that PM 10 is mostly influenced by activities and other factors that do not take place in the kitchen. Concentrations of SO 2 differed significantly depending on the fuel type used for cooking with coal gas producing 87.6% higher SO 2 concentrations than natural gas. Concentrations of CO 2 and PM 10 were the same regardless of gas type. The type of ventilation was found to influence polluant concentrations with a mechanical exhaust system showing higher efficiency than a natural ventilation system in exhausting pollutants. The period and style of cooking also affected concentrations of pollutants in the kitchen.