Structural Strengthening of Brick Masonry Walls of Heritage Building with Carbon Fibre Reinforced Polymers

S. K. Savardekar, Director, FYFE (India) Pvt. Ltd., Mumbai, V. Jain, Director, FYFE (India) Pvt. Ltd. Delhi and K. R. Raikar, Director, Structwel Designers & Consultants Pvt. Ltd, Mumbai.

A sprawling palace complex built in 1893 and belonging to the Nizam family, rulers of the erstwhile princely state of Hyderabad in India, is currently being developed as a luxury heritage palace hotel by a leading hotel group from India. Various functional buildings are integrated to form the palace complex of around 940,000 square meters area. The original construction of the palace features mainly a load bearing masonry structure comprising burnt clay brick masonry in lime mortar. Years of disuse and exposure to environmental vagaries, had resulted in various distresses to the structures. The present developers thought is it prudent to conduct a structural audit of the palace complex to assess the present condition of various structures. Subsequent to a structural audit, it was noted that amongst other anomalies, various sections of the load bearing masonry walls of various buildings were non-compliant to the allowable values of slenderness ratios. This necessitated certain intervention measures to the deficient masonry wall panels. An intervention scheme using carbon fibre reinforced polymer (CFRP) bands as localised intermediate stiffeners onto the walls was found appropriate and thus adopted considering various advantages it offered. This paper describes the site case study on the installation of a particular proprietary CFRP system in achieving the desired objective of carrying out structural intervention of masonry walls.

Introduction

Project Description
Structural Strengthening
Figure 1: Front façade view of the main palace building
A leading hotel group in India has recently commenced development of an existing old palace complex to be converted into a luxury heritage hotel. The palace complex belonged to the Nizam royal family, of the erstwhile princely state of Hyderabad in southern India. The construction had commenced in 1884 and is said was completed in various stages over a period of nine years. The palace complex comprises various functional buildings such as the main palace, Gol bungalow, Zanani mahal and various other ancillary buildings all integrated to form a sprawling complex covering around 940,000 square meters. Fig.1.

Need For Structural Intervention

The various buildings of the palace complex are predominantly load bearing type and constructed of burnt clay brick masonry with lime mortar rendering. Certain sections of the walls at the ground level, are noted to be of stone masonry with lime mortar. Over the years, the palace complex was in state of disuse and had been exposed to environmental vagaries.

Certain sections of the palace buildings exhibited distresses in the form of cracks in the masonry and even partial collapses of the masonry walls at few locations were evident. The developers have therefore considered it prudent to conduct a structural audit of all the palace buildings to determine its suitability for their proposed use and the resulting loading conditions. The developers had thus appointed structural engineers for this purpose. Various surveys, visual inspections, non destructive and partially destructive tests and analysis had been conducted by the structural engineers. Based on their evaluation, the structural engineers had identified certain structural anomalies. One amongst the various anomalies having relevance to this paper was that certain masonry walls of various buildings of the palace complex being slender. This necessitated localized structural intervention to address the issue.

NBM&CW June 2011