Masonry Magazine September 1976 Page. 22
TYPICAL FLOOR PLAN
The structural system for the Hanalei Hotel addition used concrete masonry walls with precast lift-on-slab concrete floors. The eight-inch wide masonry walls have a design strength of 3,000 psi under the special provisions of the 1964 Uniform Building Code.
The masonry contractor (Quality masonry and F. B. McCauley Joint Venture) started work on the 25th of February; from then on, the job proceeded at the rate of one floor finished each week. Progress pictures taken each Friday afternoon show the crane in approximately the same spot week after week, setting the precast floor slabs. One architectural advantage of using precast flat slabs is reduced floor to floor heights. In the Hanalei, we saved the cost of one story of concrete block by using 8'-8" floor to floor heights, eliminating suspended ceilings in motel rooms and applying ceiling finishes directly to the slab bottoms. We have continued to apply this method on subsequent projects. We have varied heights from 8 feet to as high as 9-2" for 2nd floors and above and up to 13'-2" for first floors with public facilities.
San Diego Hilton Addition
The 8-story hotel addition to existing facilities is located on a 17 acre beach front site, contains 74,516 SF and 127 rooms with private balconies. The structural system is similar to the Hanalei Hotel in that they both rest on a thick mat foundation over re-compacted soil, due to poor soil conditions. All floor and roof slabs were job cast and lifted in place by use of a truck crane. The similarities end at that point of reference. The Hilton Inn has a double loaded corridor and a very tight site for casting beds. These two conditions and some rain during soil compaction operations and crane movement times added unexpected construction time. However, the block work progressed beautifully.
The double loaded corridor necessitated crane movement to two sides of the building to lift job-cast concrete slabs in place on masonry walls; where in the single loaded Hanalei the crane worked one side of the building between stacked concrete slabs, and each slab could be placed in less than 1 hour. Each room size slab varied in weight from 9 to 14 tons, sizes varied from 29-1" by 20-4½" to 33-81½" by 14-1". Since all slabs were cast on one side of the building, some close and some in an adjacent parking area, many had to be moved twice-one onto a flat bed truck, and then from the truck by the crane into place. The double movement also was caused by the poor soil condition around the building. When the ground was dry the truck crane could pick up slabs and move them to required position with no trouble. After the rain the poor soil could not take the load of both a moving crane and a 14 ton slab. Site tightness also made the spread out casting, so successful in the Hanalei, impossible. Since slabs can't be cast higher than the workman can easily place concrete in layers, some casting beds were also used twice.
That is, after the original 8 to 10 slabs were placed, more were cast on the same bed. Due to these job conditions the construction time ran 216 calendar day time from ground breaking to first customer. Production of "high stress" concrete block for the Hilton was relatively an easy and routine job for the block producers, Modern Block of Oceanside. Most of their regular production averages 2800 psi, so it was decided a unit that averaged 3600 to 3900 psi would be advisable to produce prisms of the required 3000 psi.
The use of texture (4" high split face) block on the exterior and regular 8" high precision block on the interior, created some material handling problems at the plant because of the 53 different sizes and shapes involved. To compound this, the mason contractor had found in their previous high rise construction experience that it was expedient to cut labor by having pre-packaged material with all sizes and shapes to coincide with each individual wall section. Each floor required 16,053 concrete block units that were broken down into 79 packages which resulted in 153 cubes of block. The building was then divided into four quadrants and block was delivered with the appropriate number of packages for each section. This saved valuable space on an already limited job site. It enabled material to be placed close to the building, thus, saving rehandling on the part of the mason contractor (Custom Masonry) and it saved the manufacturer the pressure of delivering 12 loads of block at one time.