Journal of Performance of Constructed Facilities

The monitoring of deformations of the stone structure of Charles Bridge in Prague proved the gravity and relevance of nonstress effects (temperature, moisture content) on cyclic deformations and permanent strain accompanied by a gradual disintegration of its stone masonry, growing tilt of the breast walls, and development of cracks in the masonry of the stone bridge structure. Each deformation cycle is accompanied by a gradual growth in permanent deformations. The “unmanifested” primary deformation due to, e.g., a temperature change causes a mechanical state of tension, and it is mainly the tensile stresses thus arising that contribute to the development of tensile cracks in the stone masonry.

The paper is a follow-up to the first part devoted to an analogical problem investigated with a view to the degradation of the stone structure due to the effects of nonstress load, and it deals with the probability problem of the bridge structure collapse under the effect of an extreme flood wave. The paper presents the results of the numerical analysis of the response of the historic stone bridge structure of Charles Bridge of the 14th century to the flood wave effect simulated by angular rotation, subsidence, and shifting in the footing bottom of a bridge pier. Special focus is on the effect of interventions into the stone bridge structure dating back to the last major overhaul of 1967–1975, particularly, on the effect of the reinforced concrete slab (tie plate) connecting the opposite bridge breast walls increasing the rigidity of the breast walls and their structurally efficient connection to the vaults of the bridge arches. The numerical analyses performed point out the prevailing negative effects of the implemented interventions in terms of structural rigidity of the stone bridge structure exposed to the effect of a flood wave.

A blast test was conducted inside a conventional, two-story, unreinforced, brick, bearing wall building scheduled to be demolished. A credible explosive device was placed inside the building on the ground floor and was detonated to investigate whether or not the building would collapse. The measured blast pressures, key material properties of the structure, and the structural configuration were used as input parameters to a single-degree-of-freedom software program, the single-degree-of-freedom blast effects design spreadsheet (SBEDS), commonly used in the United States to model unreinforced masonry walls subjected to blast loading. The net effect of overburden loads on the ground-floor bearing walls, including uplift by blast pressures on the ground-floor ceiling, was considered when investigating the validity of an appropriate resistance function (available in SBEDS) that defines out-of-plane bearing wall response. Comparisons were made between analytical and experimental permanent wall deflections and two alternatives, a simple displacement-based criterion and a resistance criterion, were used to estimate the building’s state relative to its estimated collapse limit state. It was found that SBEDS was able to model the experimental deflections quite well if effective input parameters were carefully considered. As a result, analytical and experimental determinations of the structure’s state were also in good agreement.

Precast-concrete, skewed bridges with integral abutment walls are, typically, designed as simplified plane rigid portal frames, neglecting the degrading effects of the skew angle, the influence of haunches between the abutment walls and the deck, and laterally unsymmetrical vertical loading. This practice produces underdesigned bridges for certain aspect ratios. It is well known that the higher shear and torsional moments near the obtuse corners cause cracking and local deterioration. To evaluate the limitations of this practice, an experimental and analytical study was carried out for the live load response at the linear service level. It has been observed that for certain bridge configurations, both the positive and negative moment stresses are higher than the stresses given by plane frame analysis. The presented qualitative results enable comparison of performance characteristics.

Safety of a highway infrastructure system depends very much on the proper maintenance of bridges. The level of required maintenance is, typically, determined through a series of regular field inspections with the guidance of safety–economy trade-off. In Turkey, bridge maintenance, repair, and rehabilitation are currently performed on an as-needed basis. Time-dependent reliability analysis cannot be utilized for Turkish bridges for the time being since the majority of the bridges are either not regularly inspected or not inspected at all. The purpose of this paper is to propose a simple method to assess the remaining service life of a bridge by defining a relationship between its current condition rating and its age by evaluating a set of bridges at different ages. In a case study, 28 bridges were inspected for the first time to assess the average life expectancy. The average life of a bridge was predicted to be $80\text{years}$ , and for this set of bridges, the main body components were found to deteriorate more than earth retaining and serviceability components.

The technical note considers the cost effectiveness of risk mitigation measures for protection of buildings to terrorist threats. Protective measures might include vehicle barriers, perimeter walls, blast resistant glazing, strengthened perimeter columns, etc. Indicative values of attack probability and characteristics of commercial buildings in the United States are described. The cost effectiveness of protective measures are calculated from a preliminary economic decision analysis that includes cost of the protective measures, attack probability, reduction in risk due to protective measures, and failure consequences. Economic risks due to terrorism are compared with risks from hurricane and seismic hazards.