Journal of Performance of Constructed Facilities

This paper describes an investigation of curling problems in steel‐fiber‐reinforced‐concrete airport pavements. All the pavements were relatively thin with large plan dimensions. Analysis showed that only small amounts of differential shrinkage between the top and bottom of the slab could cause curling in these large, relative thin slabs. The most likely cause of the differential shrinkage was early‐age shrinkage due to some combination of autogeneous and temperature‐induced shrinkage, possibly compounded at later ages by drying shrinkage. When these curled slabs were opened to traffic, they cracked, forming corner breaks. Improper joint spacing was also found to be the likely cause of longitudinal cracking that developed at three airports. Problems with curling can be reduced by using low‐friction interfaces between the slab and underlying material, but the most reliable method to avoid the curling problems would be to reduce joint spacing.

Numerous workers are injured or killed each year due to trench caveins. The cause of death in many cases is due to suffocation or the force of the cavein, which causes a crushing injury to the chest. Utility‐trench excavations frequently have little money available for subsurface exploration, and the trenches extend over long distances. Because of these factors, there are more opportunities for cave‐ins in utility trenching. The paper describes a case history dealing with the collapse of utility‐trench shoring. There were two lessons learned from this case history. The first was the presence of a parallel storm drain surrounded by sand backfill that was categorized as running soil. Loss of support from the storm‐drain backfill allowed the shoring uprights to slide downward. The second lesson was that the shoring uprights did not extend all the way to the bottom of the trench. If they had, they would not have been able to slide downward and cause the collapse of the shoring system.

This case study presents the implementation of a constructability program within the petrochemical industry. Owner commitment to constructability is demonstrated by the early involvement of both the prime constructor and a constructability consultant. Formalized project‐specific procedures were developed, and detailed logs were kept in an attempt to quantify the cost and schedule benefits attributable to the constructability program. A curve presenting relative timing at which constructability benefits were achieved was created using saving estimates obtained. This graph validated a curve previously developed by the Construction Industry Institute, at the University of Texas at Austin, that showed more benefit to the project is accomplished through incorporation of construction knowledge and experience, particularly during the planning and design phases. Additionally, this paper documents a constructability program implemented at the project level and identifies perceived key elements that contributed to its accomplishments. As a practical matter, formal constructability programs are developed to facilitate interdisciplinary communication between construction and design engineering personnel. Such interaction enhances the ability to achieve project objectives and reduces the likelihood of experiencing either catastrophic or serviceability failures.

The proper use of the concepts and realities of failure is essential for successful design practice, which involves proper engineering judgment. Among the most valuable sources of good design judgment are case studies of how great engineers designed against failure. John Roebling is among the engineers whose works provide excellent models of good judgment and the explicit use of the knowledge of failures in designing successful structures. Roebling's use of failure concepts and case studies to avoid failure in his own designs provides a paradigm for good engineering practice generally. Although the analytical state of the art has certainly advanced since Roebling's time, the basic ideas of good engineering practice are no different now than they were in the 19th century. It therefore follows that a study of the methods of model engineers like Roebling can help develop judgment in modern engineers and thereby reduce the occurrence of failures in modern designs.

The outside lamina of an exterior insulation and finish system is typically applied as a plaster using a polymer and portland cement mix, reinforced by a mesh that is usually a glass fiber product. Observations of leakage and cracking are discussed. Engineers sometimes find a particularly severe cracking failure in which the crack splits the system, including the mesh, fully through its thickness, suggesting that in such cases the mesh is of insufficient strength to distribute tensile strains and control cracking. Elementary stress analysis establishes the conditions under which such full splitting will occur. Pilot tests were performed to measure elastic modulus, rupture stress, shrinkage strain, and mesh strength. For the sample system studied, the measured properties confirm the mesh strength to be inadequate for control of cracking, and predict system performance failure by full splitting. Further analysis demonstrates that the tensile strain field producing such failure can be produced solely by shrinkage of the material.

An evaluation of a masonry structure was undertaken after damage was caused by surface subsidence due to a sinkhole. The sinkhole was probably present for a long time prior to the damage, but the growth of the sinkhole was accelerated by rainwater percolating into the subgrade beneath the structure. The rainwater flowed beneath the building because of improper grading of a parking lot beside the building. Geotechnical and structural investigations were undertaken of the site and structure. The findings of these investigations are discussed, along with other findings of long-term distress to this structure. One possible recommended repair procedure is discussed, along with recommendations for construction on karst terrain and proper drainage and grading around buildings.