Anchors Testing Meets the very Strict OSPHD Requirements
The Loma Linda University Adult Hospital in the city of Loma Linda near Los Angeles was built in 1967. The hospital is outdated, overcrowded and no longer meets current seismic safety standards. Consequently, in 2016, construction work began on a new Adult Hospital as well as an additional tower for the adjacent Childrens Hospital.
The new hospital complex will not only be the tallest building in San Bernardino County, but it will also be considered one of the safest in California.
The project implements a first of its kind vertical earthquake isolation system which separates the building from the ground using more than 200 vertical shock absorbers– a large scale version of a modern car suspension system. Working together with a lateral earthquake isolation system of sliding bearings and dampers, the system will keep the hospital operational following a potentially catastrophic magnitude 7.9 earthquake.
Over 12m (40ft) of the new building will be below grade. The excavation is supported on all 4 sides by a soldier beam lagging wall, which is tied back by 4 rows of double corrosion protected (DCP) DYWIDAG Anchors.
In total, 675 36mm Ø DYWIDAG THREADBAR® Anchors and 44 46mm Ø Grade 150 DYWIDAG THREADBAR® Anchors in lengths of 9-18m (30-60ft) were installed.
Each anchor was post grouted within 24 hours after initial grouting to enhance its bond capacity. All anchors passed the required tension tests and were accepted under the very strict Office of Statewide Health Planning and Development (OSPHD) requirements. DSI USA also provided stressing equipment for anchor testing.
Among the 719 anchors supplied, 13 were equipped with the DYNA Force® system for load monitoring during and after the wall construction. The sensors were located in the unbonded length of the anchor, approx. 1m (4ft) below the bearing plate, with only the wire protruding through the bearing plate. The anchor force can be read in kips without unit conversion from the portable readout box whenever required.
The new hospital is scheduled to open in 2020.