Simplified Seismic Sidesway Collapse Capacity-Based Evaluation and Design of Frame Buildings with Linear Viscous Dampers

This article describes a simplified procedure for estimating the seismic sidesway collapse capacity of frame building structures incorporating linear viscous dampers. The proposed procedure is based on a robust database of seismic peak displacement responses of viscously damped nonlinear single-degree-of-freedom systems for various seismic intensities and uses nonlinear static (pushover) analysis without the need for nonlinear time history dynamic analysis. The proposed procedure is assessed by comparing its collapse capacity predictions on 272 different building models with those obtained from incremental dynamic analyses. A straightforward collapse capacity-based design procedure is also introduced for structures without extreme soft story irregularities.     

Displacement-Based Design of an Energy Dissipating System for Seismic Upgrading of Existing Masonry Structures

A displacement-based method for the design of an energy dissipating system is proposed in this article. The device, which is composed of added concrete walls equipped with hysteretic Added Damping and Stiffness (ADAS) dampers, is aimed at upgrading the seismic behavior of existing masonry structures. The design method is based upon a simplified model of the overall structure-dissipating system. The proposed displacement-based design procedure was tested by means of inelastic response-time history analyses considering different masonry structures. The results of the analyses were compared with the seismic behavior expected from the design.     

Seismic Design Issue of Corner Slab-Column Connection

Design criteria of slab-column connections in the ACI Building Code [2011] were mostly developed from experimental results of interior connections. When dealing with corner slab-column connections, supplementary documents published by ACI Committee 352 and Committee 421 provide better explanations than the ACI Building Code [2011] and become useful references for practical engineers. However, different design values can be obtained using approaches recommended by different documents. In this article, a summary of this issue is presented. Among several design parameters discussed in this article, bi-axial moment, gravity shear ratio and column rectangularity have more significant effect to enlarge the discrepancy.     

Full-Scale Shaking Table Tests on a Substandard RC Building Repaired and Strengthened with Post-Tensioned Metal Straps

The effectiveness of a novel Post-Tensioned Metal Strapping (PTMS) technique at enhancing the seismic behavior of a substandard RC building was investigated through full-scale, shake-table tests during the EU-funded project BANDIT. The building had inadequate reinforcement detailing in columns and joints to replicate old construction practices. After the bare building was initially damaged significantly, it was repaired and strengthened with PTMS to perform additional seismic tests. The PTMS technique improved considerably the seismic performance of the tested building. While the bare building experienced critical damage at an earthquake of PGA = 0.15 g, the PTMS-strengthened building sustained a PGA = 0.35 g earthquake without compromising stability.     

Contribution of Earthquake-Resistant Design for Reinforced Concrete Buildings when Coping with External Explosions

Fanaticism, as well as social and economic crises, has provoked a significant increase in the frequency of terrorist attacks during the last two decades and, when considered together with possible accidental explosions, has lead to a higher awareness among involved staff (owners, designers, constructors, government entities). Additionally, the fact that some buildings or targets are in seismic areas while others are not leads to a blast-loading behavior comparison. This article examines the contribution of earthquake-resistant design when coping with ground-surface explosions through nonlinear seismic assessment static analyses and nonlinear time-history analyses of blast resistance assessment using finite elements.     

Impact of Modification on Ground Motion Characteristics and Geotechnical Seismic Analyses for a California Site

The impact of different modification techniques on ground motion characteristics and results of seismic geotechnical analyses is investigated for a site in California. Twenty-eight motions were selected and scaled and also modified using both time domain (TD) and frequency domain (FD) techniques. PGV and PGD of the TD-modified motions are found to be larger than their FD-modified counterparts, but slightly less than the scaled ground motion characteristics. Cyclic stress ratios and amplification factors are similar for all sets of motions. Newmark-type slope displacements caused by the scaled and modified ground motions are similar (within 25%) for a variety of sliding masses.     

Seismic Behavior of L-Shaped RC Squat Walls under Various Lateral Loading Directions

Considerable progress has been made on the research of non-rectangular reinforced concrete (RC) squat walls over the past decades. However, the experimental data of L-shaped RC squat walls remain limited, especially for their seismic behaviors under non-principal bending actions. This paper presents an experimental and numerical investigation on L-shaped RC squat structural walls with an emphasis on how varying the directions of lateral cyclic loading influences the seismic responses of these walls. Four L-shaped specimens are tested under lateral cyclic displacements and low levels of axial compression The variables are axial loads and lateral loading directions. The performance of specimens is discussed in terms of cracking patterns, failure mechanisms, hysteretic responses, deformation components and strain profiles. Furthermore, three-dimensional finite element models are developed to supplement the experimental results. The direction of lateral loading is found to have a significant effect on the peak shear strength of L-shaped RC squat walls.     

《馆藏文物防震规范》关键技术——防震安全设计研究

《馆藏文物防震规范》WW/T 0069-2015,基于馆藏文物防震安全提出馆舍、展陈和文物全系统防震安全理念、设计方法和具体措施。本研究针对馆藏文物防震设计方法、适用范围、展柜及文物安全性判别等关键技术问题展开研究。首先,提出了"地震波+馆舍+展柜+文物"的全过程全系统防震设计理念;其次,针对浮放展柜及文物,进行地震作用下安全性分析研究;第三,与Getty博物馆研究成果对比,验证本研究理论的正确性与可靠性。分析得出:文物防震安全与文物高宽比、支撑接触面摩擦系数、安放处加速度峰值等因素有关;引入了抗滑动安全系数和抗倾覆安全系数进行设计,可充分保证文物安全性。     

Identifying integrative built environments in the archaeological record: An application of New Urban Design Theory to ancient urban spaces

Ancient Maya settlement patterns have long been described as dispersed. Instances of low-density or dispersed urbanism among agrarian-based societies are common in tropical civilizations, and are of particular interest due to their expressed problem of social integration. Traditionally, archaeologists have focused on classic hallmarks of state integration, including force, infrastructural control, large-scale ritual, and kinship; thus, reflecting the polar extremes of integration. Current models accord a more multi-scalar and dynamic nature to state and urban organization, and the need to pursue diachronic perspectives that consider more subtle and varied degrees of integration. With regard to settlement, examining the total patch of occupation on a landscape, how it developed, how it was divided up, and in turn brought together, is of interest. In this study I apply criteria developed in New Urban Design Theory, a body of thought and practice concerned with modern-day issues of dispersed and low density settlement, to evaluate an architectural complex at the Classic Maya centre of Buenavista del Cayo, Belize, believed to have functioned as an integrative space within the civic entity.     

Effective Teaching of Research Design in Physical Geography: a case study

A problem-solving approach to the teaching of research design in physical geography is introduced. Focusing on the study of the effectiveness of a local river restoration scheme, students are empowered with the responsibility for and control of their learning by means of group discussions and decision making in a series of workshops. With carefully staged guidance by tutors, students devise research questions and execute their project, analysing data collected on a field day. Although students may find this approach to be challenging and demanding, they acquire research experience and develop key skills, such as visualisation of problems and capacity for logical thought, aided by critical self-appraisal of their performance. Such an approach is particularly relevant today because of subject benchmarking skills. Developing transferable skills, such as initiative and teamwork, valued by employers also promotes self-confidence. Using a case study, this paper considers the experiences of students and staff with this approach, identifying its strengths and weaknesses, and offers possible options for its development.