宁波保国寺大殿残损分析及结构性能研究

宁波保国寺大殿是江南最古老、保存最完整的木结构佛教建筑,目前损坏较为严重.为更好地保护和修缮该建筑,残损分析和结构性能研究是其修缮加固的科学基础.首先通过现场调研,对大殿的残损状况进行分析,找出其可见的病害;然后通过精确测绘及有限元模拟分析其结构性能,找出其隐在的病害;最后,综合残损分析及数值模拟结果,提出相应的修缮建议.     

泰州水关遗址结构分析及修缮设计

水关是古城墙建筑的一个重要元素,对研究古城墙布局及城市演变具有重要意义。为了对泰州水关遗址进行科学保护,首先通过现场调研,对泰州水关遗址的残损进行分析,找出其可见的病害,包括墙体残损、基础残损、券体残损及木桩残损;然后通过有限元模拟分析其结构性能,找出其隐在的病害,主要是地基和墙体问题。最后,综合残损调研及数值模拟结果,提出了适用于水关遗址的修缮设计方法,包括地基加固、墙体加固以及木桩保护方法。     

明代石拱桥襟湖桥保护技术研究

为了对南京明代石拱桥襟湖桥的科学保护技术进行系统研究,首先通过现场调研,对南京明代石拱桥的残损进行分析,找出其可见的病害。然后通过ANSYS有限元模拟分析其结构性能,找出其潜在的病害,并进行结构构件的重要性分析。最后,综合残损调研及数值模拟结果,提出了适用于明代石拱桥的保护技术,得出的结论可供同类型石拱桥的加固修缮参考。     

淮安板闸遗址的结构安全评估与保护设计研究

为了对淮安板闸遗址进行科学合理的保护,首先通过现场测绘调研,获得板闸遗址的几何尺寸和结构构造形式;然后再对板闸遗址的残损进行分析,先找出其显见的病害,包括墙体残损和木桩残损等;接着分别采用有限元分析方法与传统计算方法对其结构性能进行研究,并进行两种方法的对比分析,然后找出其隐在病害,主要是各层土体局部塌陷和墙体开裂等问题;最后,综合实际残损分析及数值计算模拟结果,提出了适用于板闸遗址的保护设计方法。研究表明:对于板闸这类平面转折的文物类型进行修缮时,应采取适当措施增强墙体拐角处的抗拉强度,具体措施可以采取通过沿水平灰缝埋设不锈钢钢筋的方式进行加固。     

明代石拱桥永昌桥的加固修缮技术研究

为明晰明代石拱桥的结构性能,并提出适宜的加固修缮方法,以典型的明代石拱桥永昌桥为例进行研究。首先对其进行精确测绘,获得其准确可靠的几何信息;然后对其建筑形制、构造工艺及残损状况进行研究,为结构性能分析提供依据;接着利用ANSYS软件建立永昌桥主体结构的有限元模型,进行包括荷载影响分析、重要度分析和裂缝分析的结构性能研究;最后基于现状分析和结构性能研究,通过对比拱背套钢筋混凝土拱加固法和拱背粘贴碳纤维布加固法对石拱桥的结构性能的影响,提出了明代石拱桥永昌桥的加固修缮方法。研究成果可为同类型石拱桥的加固修缮提供参考。     

青海省贵德县尕让乡白马寺大经堂院落修缮保护工程述要

本文通过对青海省海南藏族自治州贵德县尕让乡白马寺大经堂院落保存现状评估及残损病害的分析,提出切实可行的修缮保护技术措施,为当地同类型寺庙的保护与传承提供修缮保护方法实例。     

民国时期钢筋混凝土结构常见缺陷及适宜性加固方法研究

民国时期钢筋混凝土结构使用年代较长,一般已超过合理使用年限,有不同程度的损伤,迫切需要加固修缮.但由于其大多为文物建筑或保护性历史建筑,承载着一些历史信息与文化价值,对其加固修缮应在充分保存历史信息的前提下合理进行结构性能和耐久性的提升.为了科学化、规范化地保护民国钢筋混凝土建筑,通过对典型案例的现场检测和调研,对这类建筑的常见缺陷进行分析和总结,结合保护原则,分别对混凝土柱、混凝土梁和混凝土板提出针对不同损伤程度的适宜性加固修缮方法.     

应县木塔结构监测与试验分析研究综述

应县木塔历史悠久,结构复杂,其主要结构构件及构造做法基本上保留了原建时期的面貌,是研究我国早期古代建筑技术及大木制度的重要实物遗存,具有独特的艺术价值和极高的科学价值和成就。然而,由于年久失修。再加上民国时期的错误修缮和战争年代的炮弹袭击以及后来多次地震的损伤累积,当前,应县木塔二层明层结构倾斜变形严重,底部三层结构病害缠身,结构亟须修缮加固。近80年来,国内数十家单位参与应县木塔保护和研究工作,取得一些成果,为制定应县木塔保护方案提供了理论依据和基础数据。本文围绕应县木塔结构试验、结构计算及结构监测等几个方面的工作,梳理和归纳了应县木塔结构监测与试验分析的研究现状,并提出现存问题和建议,供相关研究和技术人员参考。     

山西长子布村玉皇庙中殿散斗尺度与传统加固方法初探

布村玉皇庙位于山西省长治市长子县慈林镇布村村北,坐北朝南,二进院落,院内中殿呈现明显的早期建筑特征。在修缮过程中,发现文物建筑的木构件存在不同程度的残损。文章以布村玉皇庙中殿前檐铺作中的一件残损散斗为例,对其材质、形制及其材份制等特征进行研究分析。并根据对该件散斗的现状勘察,针对其文物价值与残损状况,探讨传统的文物保护与修缮加固方法。     

太原永祚寺无梁殿的建筑形制及结构静力性能研究

本工作以太原永祚寺无梁殿为例,研究中国特有的建筑遗产类型——明代砖砌无梁殿的建筑形制和结构性能。首先采用三维激光扫描仪进行精确测绘,获得其准确的几何尺寸信息。然后结合历史文献资料,对该类型建筑遗产的建筑形制进行分析。另外,通过采用无损检测方法获得砖砌体的材料强度,结合精确测绘获得的几何尺寸信息,采用ANSYS有限元软件建模并对其受力性能进行了模拟分析,获得了该建筑在静力荷载作用下的结构性能。研究结论为该类型建筑遗产的加固修缮提供参考。     

STRUCTURAL RESPONSE AND DAMAGE ASSESSMENT BY ENHANCED UNCOUPLED MODAL RESPONSE HISTORY ANALYSIS

The Uncoupled Modal Response History Analysis (UMRHA) method developed by Chopra et al. is modified in this paper to estimate damage to welded moment-resisting connections in a steel frame (MRSF) subjected to earthquake ground motions. The behaviour of these connections is modelled by a moment-rotation relationship that accounts for the cracking of the beam flange-to-column flange groove weld. The behaviour of the frame is approximated by a sequence of single-degree-of-freedom (SDOF) models for the first three modes to allow for the contribution of higher modes of vibration. The dynamic properties of these SDOF systems are determined by nonlinear static pushover analyses of the building frame. Because of the significant drop in connection strength caused by beam-to-column weld cracking, the pushover procedure uses a changing rather than invariant distribution of horizontal loads, while the structural responses are calculated from shapes that are based on the displaced shape of the frame after damage occurs. The accuracy of the method is demonstrated by a comparison with the results of a nonlinear time history analysis of the frame. This method can be used for rapid assessment of seismic damage or damage potential and to identify buildings requiring more detailed investigation.     

四川广汉龙居寺中殿建筑热湿环境特征研究

为了解广汉龙居寺中殿建筑热湿环境特征,采用基于物联网技术的环境温湿度监测系统对建筑空间温度和相对湿度进行监测,分析建筑空间温湿度时空变化规律,评估建筑热湿环境特征,探讨热湿环境对文物保存的影响。结果表明,该建筑对外界环境温湿度变化具有较好的缓冲和隔离作用,建筑内部热湿环境对文物保存不利,主要体现在相对湿度高、波动大,湿度调控将是文物预防性保护的关键。建筑热湿环境为壁画酥碱和霉斑病害主要成因,同时促进了编竹夹泥墙体结构安全问题的发生。研究成果不仅丰富了对四川地区明代编竹夹泥墙木结构古建筑热湿环境特征的认识,而且为该建筑壁画病害和墙体结构安全问题的成因分析提供了依据。     

Shaking Table Testing of a Full-Scale Prefabricated Three-Story Timber-Frame Building

Shake table tests were carried out on a 7 m × 5 m three-story, timber light-frame building (7.5 m height) at the TreesLab laboratory (Eucentre) in Pavia. The aim of the research was to evaluate the seismic behavior of a typical Italian prefabricated timber building and to study the interaction between the individual structural components tested in quasi-static manner in a previous experimental study. The 1979 Montenegro Earthquake ground motion, recorded at the Ulcinj-Hotel Albatros station, was selected as the ground motion for seismic tests. The maximum peak ground acceleration was scaled to 0.07 g, 0.27 g, 0.5 g. 0.7 g, and 1 g in order to evaluate the building’s performance at different levels of seismic input. More than 100 instruments were used to monitor the behavior of the building during seismic tests measuring acceleration, displacement, and forces. The visual inspection shows that the building did not show any damage during all seismic tests. However the data analysis (dynamic identification, capacity spectrum, inter-story drift) confirm that during the 1.00 g test the structure went beyond its linear elastic limit. The results obtained from this experimental study suggest that the design hypotheses commonly adopted in practice for seismic analysis (e.g., in terms of force distributions between the walls, and also the behavior factor q) are not always consistent with the real behavior of timber frame multi-story buildings, and should be backed by more accurate knowledge of the contributions of the individual structural components.     

The Influence of Masonry Infill Walls in the Framework of the Performance-Based Design

In this article, a performance-based seismic design (PBD) methodology is proposed for the design of reinforced concrete buildings, taking into account the influence of infill walls. Two variants of the PBD framework are examined: The first is based on the non-linear static analysis procedure (NSP) while the second relies on the non-linear dynamic analysis procedure (NDP). Both design approaches are compared in the context of structural optimization with reference to the best possible design achieved for each case examined. Life-cycle cost analysis is considered a reliable tool for assessing the performance of structural systems and it is employed in this study for assessing the optimum designs obtained. The optimization part of the problem is performed with an Evolutionary Algorithm while three performance objectives are implemented in all formulations of the design procedures. The two most important findings can be summarized as follows: (i) if structural realization follows the design assumptions, then total expected life-cycle cost of the three type of structures, bare, fully infilled and open ground story, is almost the same and (ii) if an open ground story building is designed as bare or as fully infilled frame, real performance will be much worse than anticipated at the design stage.     

Crack Patterns Induced by Foundation Settlements: Integrated Analysis on a Renaissance Masonry Palace in Italy

This study presents some numerical results related to the analysis of the structural damage of a historic masonry building, Palazzo Gulinelli, in Ferrara, Italy. A detailed analysis of the inhomogeneities of the facade, historic documentation, and recent restoration interventions carried out in an adjacent building, suggest that the Palace underwent various modifications both on the structural configuration and on the borne loads. Such modifications might be the main cause of some differential settlements and of the consequent significant crack pattern on the load-bearing walls. Therefore, in the present paper the occurrence of a crack pattern on the facade is simulated by carrying out standard linear and non-linear finite element (FE) homogenized models; differential settlements are applied in order to reproduce the structural changes occurred over time. Previous experiences of the authors (for example, Acito and Milani in 2012 and Mallardo et al. in 2008), the current crack pattern of the building (of its facade in particular) and the monitoring data referring to some of them are the main references for the analysis carried out. The structural survey, the numerical results, and the data monitoring suggest two main conclusions: 1) a good correlation between numerical results and monitoring data is assessed, therefore the cracks can be reasonably related to past differential settlements; and 2) the cracks/damage that occurred as a consequence of differential foundation settlements reduce the ability of the facade to resist seismic actions.     

基于概率法的木构古建筑地震破坏综合评价方法

为了研究木构古建筑地震破坏状态评估的准确性,应用概率的方法,以结构损伤指数、最大层间位移角作为评价因子,建立了地震破坏综合评价模型,提出了基于概率法的木构古建筑地震破坏综合评价方法。该方法在综合现状分析与实验数据,在一定烈度下计算各种破坏状态等级中每一种破坏状态出现的概率,古建筑地震破坏状态应为概率最大的地震破坏状态,从而比较准确地判别木构古建筑地震破坏程度。并对经受过汶川地震的两种结构形式的古建筑进行了验证,从而验证了该方法的合理性和有效性。这一方法将提高木构古建筑震害预测的准确性,为古建筑抗震加固提供有效的理论支持。     

General Seismic Load Distribution for Optimum Performance-Based Design of Shear-Buildings

An optimization method based on uniform damage distribution is used to find optimum design load distribution for seismic design of regular and irregular shear-buildings to achieve minimum structural damage. By using 75 synthetic spectrum-compatible earthquakes, optimum design load distributions are obtained for different performance targets, dynamic characteristics, and site soil classifications. For the same structural weight, optimum designed buildings experience up to 40% less global damage compared to code-based designed buildings. A new general load distribution equation is presented for optimum performance-based seismic design of structures which leads to a more efficient use of structural materials and better seismic performance.     

Soils and Earthen Building Materials Used for the Buddhist Temple Complex

This article presents a comprehensive study of the local soils and historic earthen building materials used in Nako temple complex in Western Himalayas. On-site and laboratory investigations followed a holistic approach to characterize materials and identify historic manufacturing formulas. The interdisciplinary and novel methodology used for analysis of the earthen building materials combine geological, chemical, mineralogical, geotechnical, and mechanical approach. The results presented in this article enable a better understanding of material culture and advance the study of damage and decay processes found in the temple buildings. In addition, a suitable conservation and preservation strategy is presented.