Response of Test House to Vibroseis Vibrations and Environmental Forces

In response to public concerns about the damage potential of vibroseis vibrat ions, Fina Oil and Chemical Company (now ATOFina Petrochemicals) sponsored a fullscale testing of a typical residential dwelling. The test house was vibrated by four vibroseis trucks on both soil and asphalt surfaces at declining separation distances. Ultimately, the vibrators were only 13 feet from the front porch and 10 feet from the front sidewalk. Peak particle velocities of the ground motions were about 1 in/s at the house foundation. No damage to the house of any kind was produced by these vibrations, even though the vibrators were operating at 90% maximum output. Tests were also conducted away from the house to explore the vibration intensities and attenuation characteristics of the ground motions generated. The resulting vibrations were compared to previous work and found to be consistent with those results (Oriard, 1994). Changes in crack width and associated weather -induced changes in temperature, humidity, and other environmental factors were recorded every two hours for one year. Environmental effects are known to produce larger crack responses than vibrations that conform to common standards and regulated limits. That fact was demonstrated again in this case. The Test House The test house (Figure 1), located near the town of McAllen, Texas, is a single-story, single-family dwelling supported by a shallow concrete slab -on-grade foundation. This house is typical of construction for the area, and was built some time before being purchased for a test house. The primary structural system ab ove the foundation is a wood frame with wood-framed interior partitions. The roof system consists of a custom-framed, gable structure decked with plywood and surfaced with three -tab composition shingles. Interior walls are clad with gypsum wallboard and f inished with conventional architectural materials such as paint, wallpaper, and stained wood. Exterior walls are clad with brick veneer and wood, and the floor plan contains three bedrooms, 1-1/2 bathrooms, living room, dining room, kitchen, breakfast are a, laundry room, and attached 2-car garage. The structure faces approximately east on a