Consulting Services

Hess Engineering is a structural engineering consulting firm specializing in seismic and other rehabilitation and restoration, building technology, support for non-structural elements, and industrial structures. We have the capability to design associated civil and surveying work. The principal of Hess Engineering Inc. has been involved with a variety of projects. We have the latest building codes and computer programs to assist you in your projects. Our services include but are not limited to the following major categories:

Seismic retrofit of tilt-up concrete buildings: Per an ordinance passed by the City of Los Angeles, all pre-1976 tilt-up buildings with flexible diaphragm (wood or steel roof) need to be retrofitted. Soft- story buildings Water reservoirs and other tanks Structures that have been subjected to earthquake or other damage, or voluntary upgrades to achieve life safety performance or reduction of potential damage.

TANK AND RESERVOIR PROJECTS

During the past thirty-five years, Mr. Hess has personally designed several hundred steel tanks and reservoirs in high seismic regions for the water, chemical and petroleum industries. This experience began with eight years as a project engineer and manager for the Chevron Oil Engineering Department before starting his own engineering consulting practice with industrial clients that included owners, fabricators and contractors for both new and existing vessels to be repaired or retrofitted for new seismic and environmental requirements.

Tanks and reservoirs designed have included steel, aluminum, stainless steel, concrete and combinations of materials. Sizes have ranged up to over one hundred feet, with height-to-diameter ratios of 3:1 to 1:4.

Foundation conditions for these vessels have included mats, pile supported slabs, ring walls and retention rings for soft soil conditions requiring deep fill and rock drains to bedrock.

For many years, the standards used were AWWA D100, API 65 and UL 142, plus other API and AWWA publications. The seismic provisions of these documents were based on the theoretical work of G. W. Housner at Caltech and Lydik Jacobsen at Stanford, plus an empirical adaptation of that work by R. S. Wozniak and W. W. Mitchell (my supervisor at Chevron). Since that time, more studies and methods have been developed by A. S. Veletsos, M. A. Haroun, P. K. Malhotra and others, which have provided ways to analyze the interaction with various foundation and soils conditions where soil parameters and site specific response spectra can be used. Hess Engineering has utilized these methods where they apply, to produce more accurate vessel designs, which can create economies by better utilization of material and site conditions.