Advanced Materials Research Vols. 133-134

Abstract: Present study deals with the stability analysis of an existing historical monument “Safdarjung Tomb” under Seismic Load. The tomb is situated at New Delhi, India. The building is classified as protected monument by the Archaeological Survey of India (ASI). This is a ground plus two storey masonry structure with a central dome. The basic seismic parameters have been evaluated using Bureau of Indian Standards (BIS) Codal method. Distribution of lateral forces is carried out to individual piers and walls using Rigidity Approach. The seismic performance of the building is studied under the gravity and earthquake loads. The building is modeled as a two-degree-of-freedom shear-beam system. The piers, which are located parallel to the direction of earthquake shaking are assumed to provide spring action. The mass of the walls and slabs are lumped at the storey levels. The lumped masses are assumed to be connected to each other through massless springs. The degree of each mass in horizontal direction is considered, neglecting the vertical translational and rotational degrees of freedom. Stiffness of the walls parallel to longitudinal and transverse directions of the building has been computed separately which was used for computation of lateral forces in each direction. The forces so evaluated are used in pier analysis to evaluate stress induced in various elements. The majority of the structural elements were found safe and the overall structure is stable. The stresses due to shear and bending are within permissible limit

Abstract: One of the most important, valuable and remarkable elments of Persian architecture is brick masonry arch. Structural behaviour of Persian brick masonry arches has not been studied in details. Any investigation into their characteristics can be beneficial for maintenance, retrofit, restoration and reconstruction of such arches. The effect of a brick arrangement in the fabric of arches, such as Roman and barrel arrangements, on structural behaviour of brick masonry arches has been a serious controversy among architects and structural engineers for many years. In this study, micro-modelling finite element technique has been used to analyse mid-pointed arches with two different brick arrangements, i.e. Roman and barrel arrangements, under static weight load using the finite element method. Analyses have been carried out and obtained results have been discussed to describe the effect of brick arrangement on structural behaviour of analysed arches with three different span lengths.

Abstract: This paper investigates feasibility of reinforcement method for fractured granite of slab type and beam members used as components of old stone masonry pagodas. Investigation of the effect of reinforcement to flexural and shear strength is performed using the concept for the high strength concrete since the mechanical properties of granite are similar to properties of high strength of concrete. In this experimental program two types of notched specimens are intended for failures with shear and flexural cracks. Intended fractured specimens are reinforced by metal rods, so called pinning method. The rods are inserted in holes and bonded with inorganic cement. The metal rods are supposed to transfer forces by tensile resistance in flexure and dowel action in shear. Increase in shear and flexural capacities and ductile behavior after sudden yielding of the metal rods are observed. The final failure cracks in reinforced specimens occurred different from interfaces along the original cracks. Locations of metal rods, their numbers, and construction of anchored rod are main variables to be examined for guidelines for reinforcement methods.

Abstract: The proposed paper reports the results of a research on the behaviour of injected anchors in historical masonry. The purpose of this investigation was to develop a methodology to be used as a preliminary design stage for structural interventions in order to pre-qualify the real strength of this kind of anchors. Several preliminary tests in laboratory with test specimens made of concrete and masonry and a first series of in situ tests on different types of masonry were conducted to analyse the behaviour of the anchorage and of the mortar. As this test is not included in National Standard, the studied standardised methodology could be adopted as a Guideline.

Abstract: To quantify the safety of masonry arches and vaults using limit-analysis, various types of safety factors have been devised. The most well-known were introduced by Heyman: a “static factor of safety” (or load factor) assessing how vulnerable the structure is to increases in the living loads and a “geometrical factor of safety” assessing how critical the thickness of the structure is for its stability. In non seismic areas, one of the main risks of total or partial collapse of arches and vaults is excessive displacement of the supports (following walls or soil deformation). Limit analysis technique can be used to analyse this risk, quantifying movements permitted before collapse and evolution of the thrust on the supports. This analysis can be combined with pathological investigations and displacement monitoring to study the evolution of the risk and define a “kinematic factor of safety”. A software program was developed (a) to compute domains of stability for particular mechanisms of deformation, (b) to study possibility of transitions between mechanisms during deformation and (c) to interactively study the influence of movements of the supports on thrust and stability. Scaled physical models are used to validate the limit analysis approach, using an experimental rig where horizontal and vertical displacements are controlled by computer. A high-speed camera is used to study transition between mechanisms. Finally it is referred to techniques integrating this kinematic approach into a more general probabilistic approach, taking into account various uncertainties in the structure (shape, thickness, loads, movements).

Abstract: The paper presents and discusses the procedure developed for the calibration of the struc¬tural FE model of a Bell-Tower, within a wide investigation program aimed to support the preserva¬tion and restoration actions. Ambient vibrations induced by wind, micro-tremors and swinging of bells were recorded and the identified modal parameters, together with geometric and crack pattern survey were used to calibrate a 3D F.E. of the tower.

Abstract: Composite timber-masonry walls have been used in many old traditional and preservable buildings that constitute a significant part of the world cultural heritage. In this structural system the walls are composed by a timber substructure that is filled by masonry with (or without) mortar. The response of these walls to any static or dynamic loading, even of small intensity, is generally non-linear, mainly due to the complex interaction between the timber and masonry components. It is obvious that the analysis, design, strengthening and retrofitting of these composite structures demand a quite complex, reliable and effective structural model that can take into consideration all the above mentioned construction details and sources of non-linear behaviour. In the present study such a precise analytical micromodel for this structural system is further developed and demonstrated with application examples.

Abstract: The assessment of the seismic response of historical masonry buildings represents a subject of considerable importance but, at the same time, of very difficult task. Refined finite element numerical models, able to predict the non-linear dynamic mechanical behavior and the degradation of the masonry media, require sophisticated constitutive law and a huge computational cost that makes these methods nowadays not suitable for practical application. In the past many authors developed simplified or alternative methodologies that, with a reduced computational effort, should be able to provide numerical results that can be considered sufficiently accurate for engineering practice purposes. However most of these methods are based on simplified hypotheses that make these approaches inappropriate for monumental buildings. In this paper a three dimensional discrete element model, able to predict the nonlinear behaviour of masonry shell elements, is presented as an extension of a previously introduced spatial discrete-element conceived for the simulation of both the in-plane and the out-of-plane behavior of masonry plane elements. The new macro-element enriches a larger computational framework, based on macro-element approach, devoted to the numerical simulation of the seismic behaviour of historical masonry structures.

Abstract: The knowledge of historical buildings represents the necessary condition for obtaining a reliable evaluation (even if simplified) of their structural safety, especially in relation to the seismic assessment. In the case of archeological finds, the knowledge of the building modifications, due to anthropic or natural events, assumes a particular importance. The Curia, placed in the archaeological site of the Roman Forum in Rome, represents, under this point of view, an emblematic case. The several transformations suffered by the building during the centuries determine the need of a seismic evaluation able to take into account the different structural conformations and the different boundary conditions.

Abstract: The Paderno d’Adda Bridge is a marvellous riveted iron viaduct with a doubly-built-in parabolic arch that crosses the river Adda near Milano, between Paderno d’Adda (Lecco province) and Calusco d’Adda (Bergamo province), in Lombardia, northern Italy. It was completed in 1889 by the “Società Nazionale delle Officine di Savigliano” (SNOS). In this work, following a previous contribution to the last SAHC08 Conference (Ferrari and Rizzi 2008), a complete FEM model of the bridge is presented, in the attempt of querying the performance of the structure at design stage. Several static loading conditions have been carried-out in the elastic range and results have been compared to those available in the original SNOS Report (1889), with remarkable correspondence.