Journal of Pipeline Systems Engineering and Practice

Full-scale direct tension test results are presented in this paper for two steel pipelines with welded slip joints, using high quality external welds, and an outer diameter and wall thickness of 320 and 6.4 mm, (12.5 and 0.25 in.) respectively. The test pipes were loaded to complete circumferential tensile failure. The results of numerical simulations with a two-dimensional axisymmetric solid finite-element (FE) models using the program ABAQUS compare favorably with the experimental measurements. The FE results show that pipelines in the field with high quality welds can sustain maximum tensile strain of about 0.03 even with internal pressure. Assuming good welds, an allowable tensile strain level of 0.01 to 0.015 is recommended. The test results are discussed with respect to welding and inspection practices, as well as their application in the design and risk assessment of pipelines subject to large ground deformation caused by earthquakes, landslides, and subsidence.

Though differential ground subsidence (DGS) impacts the seismic response of segmented buried pipelines and increases their vulnerability, there are no fragility formulations that estimate repair rates under such conditions found in the literature. Although physical models that estimate pipeline seismic damage considering other cases of permanent ground subsidence (e.g., faulting, tectonic uplift, liquefaction, and landslides) have been extensively reported, this is not the case for DGS. The refinement of the study of two important phenomena in Mexico City—the 1985 Michoacan earthquake and the sinking of the city due to ground subsidence—has contributed to the analysis of the interrelation of pipeline damage, ground motion intensity, and DGS. From the analysis of the 122 cm (48 in.) diameter pipeline network of the Mexico City water system, fragility formulations for segmented buried pipeline systems for two DGS levels are proposed. The novel parameter ${\text{PGV}}^2/\text{PGA}$ (composite parameter in terms of peak ground velocity (PGV) and peak ground acceleration has been used as a seismic parameter in these formulations because in previous studies it has shown better correlation to pipeline damage than PGV alone. By comparing the proposed fragility formulations, it is concluded that a change in the DGS level (from low-medium to high) could increase the pipeline repair rates (number of repairs per kilometer) by factors ranging from 1.3 to 2.0, with a higher seismic intensity corresponding to a lower factor.

The construction industry is continuing to face the challenge of properly identifying existing underground utilities prior to engaging in new construction or renovation projects. Contractors need to know the precise location of existing underground utilities to increase the efficiency of the construction process and to reduce the likelihood of utility strike and interruptions. This research outlines a methodology to assist field personnel in the collection of underground utility location data that can be accomplished accurately and consistently, in a minimal amount of time, with less effort, while maintaining safety protocols. This novel process aims to create a framework to develop a permanent data collection and storage solution. The research examined various methodologies to improve the positional accuracy of underground utilities through integration of global positioning systems and laser technology. The integrated technology was tested in both a controlled environment and under actual construction field conditions. The results demonstrate that the three-dimensional position of underground utilities constructed by open trenchless methods can be collected by a single personnel using integrated technologies within an accuracy of  ±450 mm (±1.5 ft). Furthermore, the positional data of a 30 m (100 ft) long utility line can be collected within approximately 15 min including time taken for setup.

Asbestos cement (AC) pipe constitutes a significant portion of the water distribution pipes still in service in many North American cities. To understand the state of the AC pipe inventory in North America, a survey was conducted of utilities with a large percentage of AC pipes in their water distribution systems. The survey included questions about pipe inventory, breakage, working environments, rehabilitation/replacement practices, and safety- and health-related management practices. This paper summarizes data from the inventory, breakage, and working environment portions of the survey. The survey obtained relatively complete inventory information for pipe length, size, years of service, breakage condition, and water quality. Information about the nature of the soils surrounding AC pipes was limited. The survey indicated that utility managers’ perceptions of water and soil environments were not always consistent with water and soil test results. Survey data analysis identified pipe age, water quality, and pipe size as important factors contributing to the failure of AC pipes in North America.