Abstract

The paper describes in detail the application of a vibration-based structural health monitoring system installed in the “San Pedro Apostol” church of Andahuaylillas located in Cusco (Peru), a 16th century adobe church considered a representative example of South America baroque architecture. The results of three years of long-term vibration and temperature and humidity monitoring program are reported in detail in the paper, with a focus on the long-term and short-term correlations between natural frequencies and environmental parameters. The results demonstrate that an accurate estimation of the first eight frequencies in the range 2-6 Hz is possible in the case of complex adobe structure and the existence of an annual cyclical behavior of the natural frequencies with a clear correspondence with the changes in environmental conditions due to seasonal influences. The performed correlations of ambient conditions and structural parameters confirmed the presence of different timescales and their not negligible influence in the case of a vibration-based structural health monitoring assessment of adobe systems with large thermal inertia large thermal inertia.

Abstract

When completed in 1961, the roof of St. Charles Church became the largest unbalanced hyperbolic paraboloid structure in the world and the only shell structure in Spokane, WA. Situated on an 8-acre site on the north side of the city, St. Charles is a modernist structure designed through partnership of Funk, Molander & Johnson and architect William C. James. This asymmetric structure is over 45.72m (150ft) and utilizes folded edge beams that taper from 1067mm (42in) at the base to a 76.2mm (3in) thickness at the topmost edge using regular strength reinforcing steel and concrete. The novelty of the shell structure serves both architectural and structural design criteria by delivering a large, uninterrupted interior sanctuary space in materially and economically efficient manner. Having previously completed an initial analysis of the structure, now, 60 years later, a complete structural forensic evaluation of the shell has been conducted using full point cloud laser scanning to generate a complete in-situ model. The in-situ geometry and historic loads are described and deflections as first steps in a full structural forensic study. Results of the current in-situ geometry are compared to the design geometry of original construction documents.

Abstract

This paper presents an application of Membrane Equilibrium Analysis (MEA) to a historic masonry arch railway bridge in Leeds, United Kingdom. This case study structure is representative of the many masonry arch bridges present on UK and European railway transport networks. It has been chosen because, since 2016, it has been the subject of a detailed Structural Health Monitoring (SHM) campaign, making it an ideal candidate against which to test analytic models. Typically, asset engineers will be responsible for maintaining a large stock of these structures and will lack the time to perform thorough computational analyses. Therefore, simplified approaches, such as MEA, which can offer insight into structural behaviour, have the potential to be highly valuable. This study represents the first step in applying MEA to masonry arch railway bridges.

Abstract

Alan Conisbee & Associates and Richard Ireland were engaged by the Royal Household Property Section to inspect and assess the historic plaster ceilings and their supporting structure within Buckingham Palace and Windsor Castle. Following the partial collapse of the Apollo Theatre ceiling in London in 2013 great importance has been placed on the inspection and certification of all historic plaster ceilings throughout the United Kingdom. This paper presents the key challenges of the project included the facilitation of access to constrained spaces, asbestos removal and cleaning of delicate fabric, surveying, digital monitoring, structural and plaster defects. Furthermore we discuss the key project outcomes including lessons learnt and best practice methodologies and practicalities behind inspections of this kind. The paper concludes with an outline of significant discoveries and ongoing laboratory testing of undernailed historic timber connections.