Journal of building engineering最新文献

{"title":"Experimental and numerical study of slender concrete-encased CFST columns under combined compression and biaxial bending","authors":"Nuoxin Wu,&nbsp;You-xin Ma,&nbsp;Kang Hai Tan","doi":"10.1016/j.jobe.2025.112592","DOIUrl":"10.1016/j.jobe.2025.112592","url":null,"abstract":"<div><div>Over the past few years, concrete-encased concrete-filled steel tube (CECFST) columns have seen widespread adoption in engineering practice. Many studies have been conducted on this innovative type of short column, exhibiting excellent structural performance. Given the growing use of slender columns in practical applications, this work aims to experimentally and numerically investigate behaviour of CECFST slender columns under combined compression and biaxial bending. Six CECFST columns with varying relative slenderness ratio, load eccentricity and moment ratio were tested under pin-ended boundary conditions. Primary test results, including load–deflection curve, failure mode analysis, moment–curvature relationship and strain distribution analysis, indicated a negative correlation of structural performance with increasing slenderness ratio and load eccentricity. Subsequently, a finite element (FE) modelling approach was developed and validated against test results. The validated FE model was then leveraged to analyse structural behaviour, such as longitudinal stress distribution and contact stress between concrete and steel of the composite columns. Additionally, applicability of European code and American Specification was assessed using available test and FE data. The latter provided a more precise set of predictions by considering the varying influence of axial load on column load-carrying capacity and steel contribution on effective flexural stiffness. The analysis of this study offered in-depth insights for evaluating CECFST slender columns under biaxial bending, particularly underscoring the importance of member slenderness effect.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"106 ","pages":"Article 112592"},"PeriodicalIF":6.7,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143817025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic damage drift limits of self-centering friction beam-column joints: Prediction and application","authors":"Xiao Lu ,&nbsp;Boyang Liu ,&nbsp;Jiahao Lei ,&nbsp;Longhe Xu","doi":"10.1016/j.jobe.2025.112604","DOIUrl":"10.1016/j.jobe.2025.112604","url":null,"abstract":"<div><div>In recent years, self-centering structures have garnered significant attention as an effective strategy to enhance structural resilience, minimize residual displacements, and reduce seismic losses. However, research on the damage criteria for self-centering components remains limited-particularly in determining the inter-story drift ratios (IDRs) corresponding to various damage states. This gap has hindered advancements in performance-based seismic design and resulted in a lack of foundational data to support resilience assessments for self-centering systems. To address this issue, this study focuses on the self-centering friction beam-column joint (SCFJ) as the primary research subject. First, four distinct damage states for SCFJs are defined, and a finite element (FE) model is developed and validated. Sensitivity analyses are performed to identify key design parameters affecting the seismic performance of SCFJs. Based on typical engineering practices, a total of 432 FE models with varying section dimensions and design parameters are constructed, establishing a comprehensive seismic damage database for SCFJs. Subsequently, statistical analysis is used to determine the IDR thresholds for each damage state, and fragility curves are fitted accordingly. These fragility curves are then applied to evaluate damage and seismic losses in two six-story frame structures. Results indicate that damage in SCFJs is primarily concentrated in the reduced section, and the mean IDRs corresponding to slight, mild, moderate, and severe damage are 0.52 %, 1.07 %, 1.74 %, and 3.48 %, respectively. Under the maximum considered earthquake, SCFJs predominantly exhibit slight to mild damage, with associated seismic losses amounting to 30,500 CNY-representing a 41.6 % reduction compared to ordinary reinforced concrete joints (ORCJs). These findings demonstrate that SCFJs exhibit significantly reduced damage and lower seismic losses than ORCJs, providing a theoretical basis for future seismic performance and resilience evaluations.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"106 ","pages":"Article 112604"},"PeriodicalIF":6.7,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143817254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Understanding the Energy Retrofit Strategies Towards Net Zero Energy Building in Sync with the SDGs: A Review and Bibliometric Analysis","authors":"Md Ozair Arshad ,&nbsp;Abid Haleem ,&nbsp;Mohd. Nadeem","doi":"10.1016/j.jobe.2025.112574","DOIUrl":"10.1016/j.jobe.2025.112574","url":null,"abstract":"<div><div>The world is entering an emerging energy crisis, and with climate change, the problem has become quite complex. Here, building services play a significant role in addressing these complex issues. Therefore, the concept of Net Zero Energy Building (NZEB) has emerged as a promising solution. This study aims to underscore the latest research and associated developments in the field of NZEB, particularly in the context of energy retrofit measures (ERMs) that align with the Sustainable Development Goals (SDGs). This review-based article employed bibliometric to conduct science mapping. The science mapping includes conceptual and social structure. This analysis was carried out from 2011 to 2024, based on Scopus and Web of Science, using the VOSviewer and Biblioshiny tools.</div><div>The conceptual structures of this study identified the six main research fields and their evolution during the periods of 2011–2016, 2017–2019, 2020–2021, and 2022–2024. The NZEB research field continues to expand, focusing on sub-research areas such as indoor environmental quality, life cycle assessment, energy retrofit measures, cost-benefit analysis, SDGs, policies, and practices in sustainable buildings. Further, the social structures deal with international collaborations and educational partnerships across the globe. Furthermore, the results provide an overview and critique of research developments in NZEB and emerging themes in the field that should be further explored in future studies, and propose a holistic model with integration of circular economy, blockchain, and triple bottom line (TBL) framework. The article gives direction to researchers, policy-makers, practitioners, and designers in developing NZEB strategies in building services. Overall, it is quite useful for all those who explore the area and try to conduct research. This bibliometric-based review may be the first article to provide an understanding of how and what efforts are being undertaken to address ERMs aligned with SDGs towards NZEB.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"106 ","pages":"Article 112574"},"PeriodicalIF":6.7,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strength growth mechanism of lithium carbonate modified high-fluidity calcium sulphoaluminate cement-based mortar for rapid repair","authors":"Xiaobing He ,&nbsp;Huixin Huang ,&nbsp;Liang Wang","doi":"10.1016/j.jobe.2025.112600","DOIUrl":"10.1016/j.jobe.2025.112600","url":null,"abstract":"<div><div>To address the temperature sensitivity during the hydration and hardening process of calcium sulphoaluminate (CSA) cement while ensuring good workability and avoiding strength retrogression, which makes it challenging to achieve rapid repair within 2h at room temperature, this study investigates the impact of lithium carbonate (LC) on the setting time, workability, and strength of CSA-based mortar incorporating mineral admixtures. The hydration process of CSA cement was characterized using hydration heat, X-ray diffraction (XRD), and scanning electron microscopy (SEM) to elucidate the modification mechanism of LC on CSA-based mortar. The findings indicate that as the LC content increases, the setting time of CSA-based mortar firstly rapidly decreases and then tends to stabilize, with minimal change in workability. The early compressive strength increases quickly and then levels off, while the flexural strength shows a general increase, thus the suitable LC content is 0.05 % of the CSA by mass; at this level, compared to the control group without LC, the 2h compressive and flexural strengths of LC modified CSA-based mortar at 20 °C are enhanced by 90.8 % and 60.1 %, respectively, and there is no retrogression in the later strength. Characterization through hydration heat, XRD, and SEM confirms that LC promotes early hydration of CSA cement, which is beneficial for the early growth of ettringite crystals and significantly modifies the temperature sensitivity of CSA-based mortar. The strength growth of CSA-based mortar is found to correlate with temperature and age through logarithmic and linear curvilinear relationships, respectively. Joint distribution functions for strength as a function of temperature <em>T</em> and age <em>N</em> as independent variables have been established.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"106 ","pages":"Article 112600"},"PeriodicalIF":6.7,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theoretical mechanism analysis and cyclic test of a improved hybrid beam through frame system","authors":"Yao Gao ,&nbsp;Quanfei Wei ,&nbsp;Yujie Yu ,&nbsp;Xiaoxiang Wang ,&nbsp;Lizhong Jiang ,&nbsp;Ben Mou ,&nbsp;Linli Duan","doi":"10.1016/j.jobe.2025.112603","DOIUrl":"10.1016/j.jobe.2025.112603","url":null,"abstract":"<div><div>An improved steel hybrid frame system, which integrates the peripheral moment frame design with the beam-through layered-column design in the interior of low-rise to mid-rise steel residential buildings, was proposed in the study. The load transfer mechanisms and deformation compatibility relationships were analyzed using structural mechanics methods. A theoretical preliminary design method was developed, and its effectiveness was validated through Pushover analysis conducted in MIDAS. A representative hybrid frame specimen was designed based on this theoretical framework. Quasi-static cyclic loading tests were performed to assess the practical hysteretic seismic performance. Results demonstrated that the hybrid frame exhibited multiple load-resisting mechanisms while maintaining clear lateral drift compatibility relationships. The damage sequences and load distributions of the indeterminate peripheral frame and interior braces can be analyzed and controlled using structural mechanics principles. Increasing the cross-sectional dimensions of the side columns and beams enhanced horizontal resistance. Certain brace location changes had a limited impact on lateral resistance. Following brace yielding, the peripheral frame accounted for the majority of energy dissipation, while post-yield strength hardening in the braces still contributed to the frame resistance increases under higher sway conditions. The hybrid frame delivered stable load resistance and excellent ductility, with the maximum drift ratio reaching 6%.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"106 ","pages":"Article 112603"},"PeriodicalIF":6.7,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143807833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cyclic Performance of Variable Grooved Gusset Plate Dampers in Cross-Braced Frames","authors":"M. Almohammad-albakkar ,&nbsp;F. Behnamfar ,&nbsp;H. Tajmir Riahi","doi":"10.1016/j.jobe.2025.112607","DOIUrl":"10.1016/j.jobe.2025.112607","url":null,"abstract":"<div><div>This study examines a novel damper designed for installation in cross-braced frames to enhance their cyclic performance, referred to as the Variable Grooved Gusset Plate Damper (VGGPD). The damper comprises a gusset plate with multiple slits arranged around the diagonal braces. The steel strips between the slits undergo significant plastic deformation under in-plane double curvature, ensuring high ductility and effective energy dissipation. The proposed damper is developed through cyclic testing and numerical analysis conducted on cross-braced frames equipped with the VGGPD. The study investigates two configurations of the damper, characterized by variable thickness and variable length, to prevent concentration of plastic deformation in a specific region. The damper plate is divided into four sections, assigning specific thicknesses or lengths to the upper and lower parts, and different specifications to the middle part. The experimental findings indicate that both damper configurations significantly improve the cyclic performance of cross-braced frames, ensuring adequate capacity to accommodate the required deformations. Furthermore, the results underscore the cyclic behavior characterized by stable hysteresis loop shapes and effective energy dissipation during repeated loading cycles. Notably, specimens utilizing the VGGPD system exhibited ductility factors reaching values as high as 8. The VGGPD system, in particular, is capable of achieving a relative drift of up to 5%, a value that matches the drift observed in special moment frames and surpasses that of special braced frames. Further validation through detailed finite element analysis in ABAQUS supported these findings, with strong agreement between the experimental and numerical results.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"106 ","pages":"Article 112607"},"PeriodicalIF":6.7,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An ontology-based approach to dynamic indoor fire emergency evacuation path planning with BIM integration","authors":"Hui Deng ,&nbsp;Zihao Fan ,&nbsp;Xinyi Wei ,&nbsp;Yichuan Deng","doi":"10.1016/j.jobe.2025.112562","DOIUrl":"10.1016/j.jobe.2025.112562","url":null,"abstract":"<div><div>The collection and updating of critical fire information remain key challenges in indoor fire emergency evacuation. This paper presents an innovative approach that integrates an Indoor Fire Emergency Evacuation Ontology (IFEEont) with Building Information Model (BIM). IFEEont is structured into five major categories, encapsulating key elements of fire evacuation. Unlike existing ontologies, it fully utilizes reasoning capabilities to infer and update node accessibility, a crucial factor in fire escape planning. A multi-sensor semantic model collects fire scene data, while ontology-based reasoning enables dynamic updates. Fire simulations conducted in an office building validate the effectiveness of the proposed method. Case study results demonstrate that the method not only captures critical fire information but also employs ontology-based inference to update node accessibility within the indoor geometric network model (GNM), effectively supporting escape route planning. Beyond serving as a fire knowledge base, the proposed ontology dynamically models fire information. This integrated approach—combining ontology, sensors, and BIM-based information updates—continuously optimizes evacuation strategies, enhances the accuracy and responsiveness of escape routes.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"106 ","pages":"Article 112562"},"PeriodicalIF":6.7,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new method to improve the carbon mineralization efficiency of steel slag in aqueous condition: The effect of mechanical exfoliation","authors":"Zhengqi Zheng ,&nbsp;Xingyang He ,&nbsp;Huahui Qi ,&nbsp;Ying Su ,&nbsp;Hongbo Tan ,&nbsp;Yingbin Wang ,&nbsp;Jin Yang ,&nbsp;Yubo Li","doi":"10.1016/j.jobe.2025.112473","DOIUrl":"10.1016/j.jobe.2025.112473","url":null,"abstract":"<div><div>The environmental challenge of global warming driven by carbon dioxide emissions is growing more severe. Alkaline industrial solid waste possesses tremendous carbon sequestration potential and is regarded as one of the most potential solutions for alleviating the greenhouse effect. Nevertheless, at present, the mainstream carbon mineralization approach internationally is the bubbling method (BC), whose inferior efficiency constrains its large-scale application. Currently, how to enhance the carbonation efficiency of solid waste is both a research hotspot and a difficulty. This paper adopted a novel aqueous carbon mineralization method by introducing mechanical exfoliation to achieve efficient carbon mineralization of steel slag (SS). The XRD results indicated that, at the same carbonation amount, the wet-grinding carbonation (GC) method results in a lower diffraction peak intensity of calcite. The PSD test results revealed that, compared with BC steel slag, GC steel slag had a smaller particle size distribution, with the median particle size ranging from 2.43 μm to 5.49 μm. According to the SEM and TGA test results, it can be discovered that due to the mechanical exfoliation effect promoting the efficient dissolution of Ca/Mg and destroying the passivation layer on the surface of SS, GC method can achieve a carbon dioxide absorption of 219.1 kg CO₂ kg CO₂eq/t within 90 min, with a rate of carbonation as high as 57.7 %, while BC method required approximately 24 h. The efficiency of the GC method is 16 times that of the BC method. Additionally, due to the smaller particle size and more active silica gel of the GC steel slag, it significantly promoted the early hydration of cement-based materials. When the content of GC steel slag was 30 %, the activity index at 28 days reached 108.5 %, and its compressive strength exceeded that of the reference mortar. This study offered new technical support and ideas for carbon emission reduction in the steel manufacturing industry and the low-carbon development of cement-based cementitious materials.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"106 ","pages":"Article 112473"},"PeriodicalIF":6.7,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feasibility study of 3D-printed rubberized concrete as a permanent formwork: mechanical properties, interlayer interface and durability","authors":"Chuanbei Liu ,&nbsp;Mengtong Zou ,&nbsp;Xuemei Chen ,&nbsp;Yongjun Deng ,&nbsp;Lihua Zhang ,&nbsp;Xu Luo ,&nbsp;Laibao Liu","doi":"10.1016/j.jobe.2025.112544","DOIUrl":"10.1016/j.jobe.2025.112544","url":null,"abstract":"<div><div>This study proposes 3D-printed rubberized concrete (3DPRC) as an innovative permanent formwork solution that integrates recycled rubber aggregates (RA) with 3D concrete printing (3DCP) technology to resolve interfacial bonding and durability limitations. A systematic evaluation of RA dosage (0-15%), particle size (30-70 mesh), and surface treatments (water-soaking, cement coating, and heat treatment) demonstrated that 5% unmodified 50-mesh RA optimizes interlayer adhesion, yielding a compressive strength of 49.78 MPa, flexural strength of 10.59 MPa, exceptional freeze-thaw resistance (&gt;600 cycles), and low chloride ion permeability (diffusion coefficient of 6.99×10^-12 m²/s). The absorption-desorption process of RA reduces surface water films on printed filaments and facilitates internal curing at interfaces, suppressing elongated pore formation and refining pore geometry. These synergistic effects enhance interfacial bond strength while mitigating mechanical anisotropy, thereby validating 3DPRC’s suitability as a high-performance permanent formwork system.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"106 ","pages":"Article 112544"},"PeriodicalIF":6.7,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of the thermal and energy saving performance of the concrete roof with radiative cooling coating","authors":"Qingdong Xuan ,&nbsp;Liang Lei ,&nbsp;Tao Wang ,&nbsp;Bin Jiang ,&nbsp;Bin Zhao ,&nbsp;Guiqiang Li ,&nbsp;Gang Pei ,&nbsp;Jian-Guo Dai","doi":"10.1016/j.jobe.2025.112578","DOIUrl":"10.1016/j.jobe.2025.112578","url":null,"abstract":"<div><div>It is recognized that a substantial portion of the cooling load in buildings originates from the rooftop, which presents a direct and opportune avenue for the implementation of radiative cooling technologies for building energy conservation and thermal comfort enhancement. In this study, a long-term field test was performed on an in-service office building with the heavy-construction roof in Hong Kong, which revealed that the radiative cooling coating (RCC) on the concrete roof could effectively reduce the rooftop outside surface temperature by 21.1 °C at the maximum. As a result, the RCC can turn the disadvantage of the high thermal mass of concrete roofs (absorbing heat during daytime and continuously releasing heat at night) into an advantage of storing coolness at night while continuously cooling down during the day, achieving a 1.5 °C lower temperature on the inside surface of the roof compared to the indoor air temperature throughout the day. When the air conditioning (A/C) system was operated with identical settings, the concrete roof with RCC consistently reduced the indoor air temperature by 2.8 °C, concurrently achieving a 20 % reduction in electricity consumption (i.e. 8 kWh per day during 8:00–18:00) as compared with the reference case. Heat-transfer building modeling analyses further demonstrated that under extreme external weather conditions and with a cooling setpoint maintained at 26 °C, the RCC significantly improved indoor thermal comfort. Additionally, it achieved an average annual cooling energy savings of 49.42 % (equivalent to 1108.74 kWh) across various cities in China.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"106 ","pages":"Article 112578"},"PeriodicalIF":6.7,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143817026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}