Journal of Performance of Constructed Facilities

A minor slide occurred in the downstream face of an earth dam. Initial observations and limited optical survey data suggested the failure was shallow, but continued measurements from inclinometers in the embankment and survey monuments, as well as visual observations of deformation patterns, revealed a more extensive and severe failure located in the underlying weathered claystone foundation. Deep inclinometers were installed, and inclinometer readings indicated that approximately 1 cm per day of movement was occurring along a very discrete zone in the foundation. Horizontal survey measurements confirmed this displacement, and an emergency soil buttress was constructed at the toe of the dam to reduce movement. The residual strength along the slip surface was estimated by back analysis of the sliding block, assuming a safety factor of 1.0 and incorporating end restraint to assess the lower-bound residual strength. The remediation scheme included installation of an internal drainage system and a soil buttress. Postconstruction monitoring shows that the dam is continuing to move at a decreasing rate and is apparently approaching static equilibrium.

An original method is presented for fatigue testing of tunnel panels that are dynamically loaded by pressure waves caused by car and truck traffic. The dynamic pressure load on the tunnel walls is measured at the site and simulated in a real-size laboratory testing procedure, in which pressure and suction loads are generated by a bellow system. The bellow system simulates the maximum loads caused by vans and small trucks. Additionally, a high frequency load is applied by means of a vibrator placed in the antinode of the most important mode shape of the panel system. The loading frequency is imposed close to the corresponding natural frequency of the panel and fixation system. In this vibration loading, the behavior of the panel system during the real life span is controlled. The testing system allows for optimization of both the panel composition and the attachment system.

There are numerous large span timber hangars dating back to World War II. These structures were built with large green timbers and were normally assembled using split rings and/or shear plates. Because of shrinkage in the timbers in the joint area, most of the structural members show severe splitting. As a precautionary measure, the capacity of the connections is usually reduced. A typical repair method is to install anticheck (A/C) bolts running perpendicular to the longitudinal axis of the timbers. Repairing members using A/C bolts is more favorable over other methods because A/C bolts are easy to install. Three groups of full-scale specimens representing typical connections in Warren truss hangars were fabricated with splits in the truss tension members, and they were tested using A/C bolts to verify the effectiveness of A/C bolts as means of repair for split connection members in large span timber hangars. Results showed that the strength of damaged tension members where splits run between split ring rows was not significantly different from undamaged tension members. In addition, A/C bolts significantly reinforced some damaged connections and could be used to reinforce undamaged split ring connections and force an ultimate ductile failure mode.

A 1987 addition to a Midwest high school included the use of a white utility brick. The original building was surrounded on three sides by the new addition, which provided a striking appearance. Approximately 4 years after the completion of the school, a number of problems, which neither the architect nor contractor were able to resolve, were examined. The problems generally fell into two categories, water infiltration and spalling of brick. Although water infiltration is not an unusual building problem, spalling brick is. It is not uncommon to see old neglected brick walls, such as parapets, saturated with water. Typically, in these instances, the face brick is intact, and the mortar has deteriorated. In this building, the opposite occurred. The brick was deteriorating, but the mortar was not.

Environmental effects and repetitive traffic applications can lead to the development of transverse cracks in jointed concrete pavements. Maintaining adequate aggregate interlock load transfer across these cracks is essential to preserving the functional and structural integrity of these pavements. The objectives of this study were to determine the design parameters that significantly affect transverse cracking and to demonstrate methods available for evaluating cracked pavements. Field data collected from in-service jointed concrete pavements located throughout southern Michigan were used to accomplish these objectives. Joint spacing, coarse aggregate type, shoulder type, and pavement temperature were found to have significant effects on transverse crack development and/or performance. The surface texture of crack faces was assessed using a promising new test method called volumetric surface texture testing. Volumetric surface texture results provided an indication of the aggregate interlock potential of pavements containing various aggregate types. Three performance parameters capable of mechanistically characterizing crack performance were discussed. A relatively simple procedure was described for determining these parameters and evaluating crack conditions. Field data were also used to demonstrate and validate a voids' analysis procedure. This procedure estimates the potential for loss of support near cracks and joints, thus allowing for proper rehabilitation actions to be taken prior to the manifestation of additional distresses.