Antonine contraction (c. AD 165–80)

London appears to have shrunk significantly in the Antonine period, although the evidence remains contested. A major concern has been expressed over whether bioturbation and disturbance has removed the evidence of slightly built timber structures, leaving us with an exaggerated idea of the scale of contraction. This chapter looks to the detail of this evidence, including the formation of a dark-earth horizon that may mark the conversion of abandoned buildings to urban wastelands, to conclude that 57 per cent of sites show evidence of contraction that cannot be accounted for by later disturbance. It is consequently estimated that London’s population may have reduced from over 30,000 to under 20,000. Depopulation was perhaps hastened by an evacuation of the military garrison from the Cripplegate fort, and is reflected in reduced settlement densities in London’s rural hinterland and the cessation of some industrial production. There were no signs of this contraction before c. AD 165, but little evidence of routine urban maintenance in the following decades. Factors that might have contributed to London’s depopulation are considered. One of the most important may have been urban flight and manpower shortages following the epidemic known as the plague of Galens. Anxiety over the effects of this plague is attested by an amulet inscribed with a magical phylactery from the Thames foreshore, and the popularity of a London cult of Apollo the archer. The potential importance of such a pandemic to the changed mentalities of later antiquity is considered.

SEGMENT OF WALL PANEL FOR TIMBER STRUCTURES UNDER VERTICAL LOAD

The subject of this paper is an experimental and numerical analysis of the stability of the wall panels with one-side board sheathing for timber structures. The reinforcement of the panel is provided using glued timber composite I-shaped element consisting of a web made of a wood-based desk embedded into flanges of solid timber. The mechanism of the behaviour of these panels, mode of the failure and reliable procedure to determine the buckling load-bearing capacity not been fully explored so far. This work describes the behaviour of the wall panel under vertical load and the method of failure using experimental and numerical analysis. The reduction coefficient kJ was determined, which can be used for a simple calculation of the buckling capacity of a wall panel.

Seismic Vulnerability Assessment and Strengthening of Heritage Timber Buildings: A Review

Recent studies highlight the potential impact of earthquakes on cultural heritage sites and monuments, which in turn yield significant adverse impacts on economies, politics, and societies. Several aspects such as building materials, structural responses, and restoration strategies must be considered in the conservation of heritage structures. Timber is an old organic construction material. Most of the historic timber structures were not designed to withstand seismic forces; therefore, the seismic vulnerability assessment of heritage timber structures in areas with high seismic hazard is essential for their conservation. For this purpose, different strategies for the numerical modeling of heritage timber buildings have been developed and validated against tests results. After performing seismic analysis using detailed analytical methods and predicting the susceptible structural components, strengthening techniques should be utilized to mitigate the risk level. To this aim, various methods using wooden components, composite material, steel components, SMA etc., have been utilized and tested and are reviewed in this study. There are still some gaps, such as full-scale numerical modeling of strengthened buildings and investigating the soil–structure interaction effects on the seismic behavior of buildings that should be investigated.

Experimental study on flexural properties of timber columns with interior notches in traditional Japanese timber structures

In this study, the columns with interior notches in traditional Japanese timber frames were selected as the research object, and static bending tests were performed to investigate the effect of interior notches on the flexural properties of columns. First, the bending behaviors of columns under three-point and four-point load configurations were compared to obtain a suitable referenced strength of a column without notches. The reduction in the load-bearing capacity of columns with different types of interior notches in traditional Japanese timber structures was determined through experimental tests and statistical analysis. The results indicated that the mean bending strength of columns with three different notch types was consistent with those without notches, the continuous timber on both sides of the notch had a beneficial effect on maintaining a higher strength and reducing the stress intensity around the notch. The fracture position and the standard deviation of the bending strength were affected not only by the notch depth, but also by the notch width on the tensile side of the column.