Arun Menon

Bio: Arun Menon is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Masonry & Unreinforced masonry building. The author has an hindex of 7, co-authored 34 publications receiving 210 citations. Previous affiliations of Arun Menon include University of Pavia.

Simplified Performance Assessment for Single-Span Masonry Arch Bridges under Live Load

Abstract: A quantitative, rapid screening assessment methodology for masonry arch bridges, with minimal input parameters, is proposed. The developed mechanism-based analysis procedure is validated a...

Structural Behaviour of Gopurams in South Indian Temples

Abstract: The multi-storied masonry “Gopuram” or the ceremonial entrance gateway, an ubiquitous structure in a South Indian temple, was a feature introduced circa 14th c. AD in order to confer architectural status to structurally insignificant ancient shrines. The gopurams of the Meenakshi Temple in Madurai (1600 AD), the Ranganathaswamy Temple in Srirangam (17th c. AD) and the Ekambareswar Temple in Kancheepuram (16th c. AD), 52 m, 72 m and 59 m tall, respectively, are representative of the highly evolved Dravidian temple architecture. The current research is an attempt to understand the structural behaviour of the gopuram with a focus on a centuries-old incomplete structure in the town of Thiruvellarai in Tamil Nadu. The paper presents outcomes of detailed field and laboratory investigations on the sub-structure, the superstructure and structural materials of the gopuram, that provide insight into the structural configuration of the gopuram. It then examines the structural response to gravity and lateral forces, through non-linear finite element models of the structure. One of the significant aspects studied is the role of the core masonry in the structural response of the multi-leaf masonry structure of the gopuram. In addition the role of floor diaphragms in the structural stability of the gopuram is investigated. The outcome of the study is expected to provide important insights to the reasons for structural distress and collapse of such structures, particularly the Vijayagopuram at Srikalahasti in Andhra Pradesh in South India that collapsed in May 2010.

Seismic Behavior of Timber-Laced Masonry Structures in the Himalayan Belt

Abstract: In many areas of high seismicity, one can witness traditional construction systems in brick masonry with timber elements. These traditional timber-reinforced constructions are based on empirical knowledge acquired through the generations in response to the natural hazards encountered. This timber-reinforced construction may be classified in to two categories, one is of timber-framed construction and another is of timber-laced construction. An important and interesting feature of these timber-reinforced masonry construction is their resilience to seismic action. In recent earthquakes (Turkey 1999, Kashmir 2005 and Sikkim 2011) these constructions showed excellent performance in contrast to the modern but unregulated multi-story RC buildings with URM infill. The seismicity of the Himalayan region in the Indian subcontinent is notorious. Several timber-reinforced construction systems have been developed in this region, depending upon the socio-economic-environment conditions; to name a few: Dhajji-Dewari, Taq, Kath-khuni and Ekra. This paper initially presents a comprehensive review of numerical and experimental studies on the traditional timber-framed constructions relevant to the Himalayan region, as there were few studies on the timber-laced masonry constructions a specific case study on Taq system had been carried out to identify critical parameters responsible for their desirable seismic performance.

Modelling and seismic analysis of existing masonry structures

Abstract: This chapter examines results of macro-element based modelling and analysis with that from a micro-modelling approach, particularly in terms of the global capacity and damage and collapse mechanisms. It deals with a word of caution on the use of macro-element modelling approaches for seismic assessment of existing masonry structures, particularly where out-of-plane mechanisms can be expected and rigid diaphragm action is not guaranteed. The chapter explains the differences in results of macro-element based modelling and analysis compared to a micro-modelling approach, in terms of the global capacity and damage mechanisms. Seismic vulnerability of a structure depends on the nature and condition of its structural materials, geometrical configuration and integrity of its structural system. In the context of mitigating earthquake effects, seismic assessment, strengthening and retrofit of the structure become important. Masonry was assumed to have a compressive strength of 3.0 MPa and a modulus of elasticity of 2000 MPa and was modelled using Rankine-Hill anisotropic continuum model.

Probabilistic Seismic Hazard Assessment of India

Abstract: Online material : Data files for seismogenic source zones (polygons), smoothed-gridded seismicity models, and hazard curves at 0.2° regular grid spacing over the study region. Earthquake disasters occur mainly due to the collapse of buildings and structures triggered by ground motions. It is, therefore, important to predict ground-shaking levels in order to determine appropriate building code provisions for earthquake-resistant design of structures. This involves extensive analyses and development of appropriate seismological models; namely, seismogenic sources, seismic site conditions, and ground motion predictions. The hazard products, viz . data and maps, constitute important tools for framing public policies toward land-use planning, building regulations, insurance, and emergency preparedness. View this table: Table 1 Major Earthquake Casualties during 1900–2008 in India and Adjoining Regions In India, several events during the last 100 years, as listed in Table 1, indicate that even moderate earthquakes ( MW < 7.0) can cause significant devastation. On one hand, ongoing urbanization and unprecedented population growth have considerably aggravated the prevailing seismic risk. On the other hand, the available seismic hazard maps covering the entire country are about a decade old. Consequently an updated seismic hazard model for the country is imperative and necessitated by new data, recent findings, and methodological improvements. In the present study, we make a case for new probabilistic seismic hazard analysis (PSHA) of India. The fundamental studies have been carried out to deliver the hazard components, including seismogenic source zonation and seismicity modeling in the Indian subcontinent (Thingbaijam and Nath 2011), assessment of site conditions across the country (Nath, Thingbaijam, Adhikari et al. 2011), and a suitability test for the ground-motion prediction equations in the regional context (Nath and Thingbaijam 2011). These components are integrated to deliver a preliminary model consisting of spatial distributions of peak ground acceleration (PGA) and 5%-damped pseudo spectral acceleration (PSA). Initial attempts at …

Peak ground motion predictions in India: an appraisal for rock sites

Abstract: Proper selection and ranking of Ground Motion Prediction Equations (GMPEs) is critical for successful logic-tree implementation in probabilistic seismic hazard analysis. The present study explores this issue in predicting peak ground accelerations at the rock sites in India. Macroseismic intensity data complemented with limited strong ground-motion recordings are used for the purpose. The findings corroborate the possible conformity between the GMPEs developed for tectonically active shallow crust across the globe. On the other hand, the relevant GMPEs in the intraplate regions cluster into two different groups with the equations of lower ranks catering to higher ground motions. The earthquakes in the subduction zones have significant regional implications. However, affinity in the ground-motion attenuations between the major interface events (MW > 7.4) in Andaman-Nicobar, Japan and Cascadia, respectively, is noted. This can be also observed for the intraslab events in the Hindukush and Taiwan respectively. Overall, we do not observe any significant advantage with the equations developed using the regional data. These findings are expected to be useful in probabilistic seismic hazard analysis across the study region.

Review of strength models for masonry spandrels

Abstract: Many older unreinforced masonry (URM) buildings feature timber floors and solid brick masonry. Simple equivalent frame models can help predicting the expected failure mechanism and estimating the strength of a URM wall. When modelling a URM wall with an equivalent frame model rather than, for example, a more detailed simplified micro-model, the strengths of the piers and spandrels need to be estimated from mechanical or empirical models. Such models are readily available for URM piers, which have been tested in many different configurations. On the contrary, only few models for spandrel strength have been developed. This paper reviews these models, discusses their merits, faults and compares the predicted strength values to the results of recent experimental tests on masonry spandrels. Based on this assessment, the paper outlines recommendations for a new set of strength equations for masonry spandrels.

Seismic assessment of existing and strengthened stone-masonry buildings: critical issues and possible strategies

Abstract: The seismic performance of stone masonry buildings is known to be generally poor with respect to other structural typologies. However, significant differences can be observed for different architectural configurations, structural details and masonry mechanical properties. In particular, the seismic vulnerability of existing stone masonry structures is often governed by local failure modes, typically consisting of out-of-plane overturning of structural portions or crumbling of outer wythes in multi-leaf walls. In buildings with an adequate masonry quality, an overall behaviour controlled by the in-plane capacity of walls can develop and govern the global failure mode, provided that proper connections between perpendicular walls and between walls and floors are effective in contrasting the activation of early local failures. In these cases, the in-plane stiffness of diaphragms (typically vaults and timber floors/roofs) can play a significant role in coupling the response of the different walls, hence controlling the global building capacity. Recent experimental testing campaigns carried out in different laboratories have focused on several aspects of the seismic response of stone masonry buildings and on the effect of several strengthening techniques. The availability of such experimental results allowed validation and improvement of analysis tools and procedures for the assessment of the seismic capacity of existing stone masonry structures. In order to make them available to all practitioners, the research achievements need to be incorporated in codes and guidelines for the assessment and strengthening of existing stone masonry buildings. The procedures currently proposed in several codes are already based on a rational approach, which starts from the acquisition of an adequate structural knowledge level and allows for using nonlinear analysis procedures. They could straightforwardly include new research findings and practical developments.