The Dynamic Behavior of the Basilica of San Francesco in Assisi Using Simplified Analytical Models

The Basilica of San Francesco in Assisi endured stronger earthquakes for centuries before 1997 earthquake, which generated the collapse of the two vaults. Experts blame as possible reasons of collapse the damage cumulated from previous earthquakes and/or the retrofitting made to the structure over its lifetime. This article presents the history of the retrofit interventions of the Basilica through the centuries, focusing mainly on the roof, which has been subjected to three major restorations through its life. It is shown using simple analytical models that the cumulative effects of the changes made to the roof of the Basilica affected the structure’s dynamic behavior in a negative manner, increasing the seismic loads on the existing structural members. In particular, the numerical results show that the 1958 roof intervention has stiffened the structure, redistributing the seismic loads on the façade and the transept. This overload might explain the collapse of the two Gothic vaults during 1997 earthquake.     

Stability of Slender Masonry Columns with Circular Cross-Section under Their Own Weight and Eccentric Vertical Load

This work concerns the stability of unreinforced masonry slender circular cross-sectional columns subjected to their own weight and eccentric vertical load. Cantilever columns are examined, considering that the material has infinitely linear elastic behavior in compression and has no tensile strength. For the analysis, an existing numerical model and solution procedure developed for the stability analysis of masonry elements with rectangular cross-section are utilized and adapted to the circular columns. For the instability of the columns, an appropriate criterion that relates the top lateral deflection to the intensity of the applied eccentric vertical load is employed. By considering a reference column, critical buckling load is obtained, behavior of the column interpreted and efficiency of the numerical model emphasized. Performing a nonlinear buckling analysis using a general purpose software on this reference column, obtained results are compared with those of the adapted procedure of the present study. Implementing parametric analyses on reference column, effects of the column slenderness, eccentricity of vertical load, elastic modulus, and self-weight on the buckling load are investigated. Presented calculation procedure provides a useful tool in order to calculate the critical loads or to check the stability of masonry circular columns.     

Simple Seismic Assessment of Traditional Unreinforced Masonry Buildings

A framework for quick seismic assessment and retrofit of traditional unreinforced masonry (URM) structures is presented. The proposed methods build on simple principles of structural dynamics and are used as an alternative to detailed time-history analysis, in recognition of the prevailing need for simple and practical methods, compatible with the low-budget and the limited level of knowledge regarding materials, internal force paths, connectivity and condition of older URM structures. An objective is to identify areas in the building that are particularly susceptible to damage and for guiding the types of the required global interventions to improve seismic response. Demand and supply are expressed in terms of relative drift ratios that quantify the intensity of out-of-plane differential translation and in-plane shear distortion of masonry walls. A characteristic traditional building type of timber-laced masonry is used as a model structure for illustration of concepts. The morphology and geometry of the building correspond to a statistical sample of the actual traditional unreinforced masonry buildings (TURM) found in historical centers of many towns in the greater region of Northern Greece. The methodology is particularly useful for setting retrofit priorities and management of the collective seismic risk of historical entities.     

清乾隆时期的宫殿建筑风格

康熙、雍正、乾隆以及嘉庆朝所建的宫殿,在传统礼制规定内,其宫殿环境、建筑布局及艺术等力求贴近现实生活。表现出创造惬意的环境和方便舒适的建筑、满足皇帝的理政及生活要求等一系列特性。这也构成了“乾隆时期”宫殿建筑的整体风格。     

清代宫廷建筑的管理制度及有关档案文献研究

本文介绍了清代宫廷建筑的管理机构与官员状况、宫廷建筑工程的各项管理制度,并列举了内阁、军机处、宫中、内务府、工部等处的部分档案,这些档案内容涉及紫禁城宫殿楼阁、苑囿行宫、陵寝、坛庙寺观、盛京皇宫及与宫殿建筑有关的河道、沟渠、园林、道路等的兴建和维修状况。这些清代档案是我们现今研究清代宫廷建筑的第一手资料,也是我们保护维修现存宫殿建筑的可靠依据,有着重要的史料价值。     

A 13th-Century Shipyard at Alanya (Alaiyye), on the Mediterranean Coast of Turkey

Anatolian Seljuks, a territorially-powerful medieval government, held their fleet at bases on the Black Sea and Mediterranean coasts, and constructed permanent stone buildings to protect their navy. Although most of these buildings have disappeared, 13th-century defended shipyard buildings have survived at Alanya, on the Mediterranean coast of Turkey. These buildings are not only important architecturally, but can give clues to the types of warships used by the Anatolian Seljuk navy, of which little is known. The dimensions of the shipsheds help us to analyse the construction of these naval vessels.
© 2009 The Author     

PROCEDURE AND SPECTRA FOR ANALYSIS OF RC STRUCTURES SUBJECTED TO STRONG VERTICAL EARTHQUAKE LOADS

Abstract

In view of the compendium of field evidence and supporting analysis work indicating the possible damaging effects of vertical earthquake ground motion, this paper addresses the problem of code-type vertical force calculation. In light of recent engineering seismology studies of the relationship between vertical and horizontal peak ground acceleration, the inadequacy of the 2/3-rule depicted by codes is highlighted. A simple piece-wise linear relationship is proposed and shown to represent existing strong-motion measurements adequately. Bilinear and inelastic spectra are derived and studied. It is demonstrated that net tensile forces and displacements may ensue, thus eroding the shear resistance of RC columns. A simple procedure is outlined whereby modal analysis may be employed to estimate conservatively vertical earthquake forces on buildings. Finally, areas of further exploration and refinement are identified.     

DEFORMATION-CONTROLLED EARTHQUAKE-RESISTANT DESIGN OF RC BUILDINGS

A procedure for deformation-controlled, or displacement-based, seismic design of multistorey RC buildings is proposed, implemented and applied for the full design of a four-storey RC structure. It is integrated into the overall structural design, along with the design for the non-seismic actions and consists of a ULS verification against the conventional strain limits for a frequent “serviceability” earthquake and of proportioning the compression reinforcement and the transverse reinforcement of critical regions of members to meet the member peak inelastic chord rotation demands under the “life-safety” seismic action. Quantitative rules and expressions are proposed for the estimation of (a) mean and upper-characteristic peak inelastic chord rotation demands, through appropriate linear-elastic analyses, and (b) mean and lower-characteristic values of member ultimate chord rotations, in terms of member geometric and material data.     

Railway development as Symbolising ideas of social construction: (With Special Reference to Railway Development in Australia)

The townscape of “old” Lerwick reflects its traditional focus on the sea for its economic base. The major elements in this cohesive visual character are the closely clustered houses in the steep hillside district of the Lanes, the narrow, winding principal commercial street, and the lodberries projecting out into the harbour. The latter were constructed to meet the needs of the prosperous expanding trade period of the latter half of the 18th century and first half of the 19th century. Harbour improvements in the final quarter‐century of the 1800s ended their commercial usefulness. After a century of declining use and of neglect they are being restored as part of the renewal of “old town” Lerwick.     

6. SPACE: A USELESS CATEGORY FOR HISTORICAL ANALYSIS?

Much fuss has been made of the “spatial turn” in recent years, across a range of disciplines. It is hard to know if the attention has been warranted. A confusion of terms has been used—such as space, place, spatiality, location—and each has signified a cluster of often contradictory and confusing meanings. This phenomenon is common to a range of disciplines in the humanities. This means, first, that it is not always easy to recognize what (if anything) is being discussed under the rubric of space, and second, that over‐extended uses of the cultural turn have stymied meaningful engagement with (or even a language of) materiality in discussions of space. This article shows how materiality has been marginalized both by a casual vocabulary and a vigorous a priori epistemological holism on the part of scholars, and how the spatial turn has been too closely linked to the cultural turn to allow it to develop its fullest explanatory potential. It demonstrates how historians might profitably theorize the significance of place and space in their work (borrowing techniques from geographers and anthropologists, and referring to the phenomenological tradition), and sets out some challenges for using space more effectively in explanatory systems. Inspired by environmental history, sociology, and science and technology studies, I propose a way of establishing space as different from conventional historical handling of materiality, and end by identifying some methodological problems that need to be solved if we are to proceed on a surer footing.