Shaw & Sons pays careful attention to the engineering details of formwork, including horizontal and vertical
layout, fabrication and installation to insure a visually smooth, code compliant finished concrete slab.
Without a well-graded and compacted subgrade, even the best architectural concrete may fail. Subgrade should consist of semi-permeable, non-expansive soils and materials, and must be graded and compacted in accordance with the soils report. Architectural concrete should always be placed over a minimum of two-inch dry, compacted and screeded, washed concrete sand. Sand allows the concrete to "bleed" or hydrate evenly on the surface, thus minimizing the potential of irregular coloration on the surface of finished concrete.
Proper subgrade preparation is the first step to correctly forming a cast-in-place project. The photos on these pages show Shaw & Sons typical procedure for installing based material and washed concrete sand. Although not specified and at no additional cost to the client, Shaw & Sons first installs Mirafi 500x Geotex fabric for soil separation and stabilization. This prevents additional cracking and displacement of concrete, keeping it securely and evenly in place for the long term. Next, sub-base or sand is installed in 4-inch lifts and saturated to specifications provided by the soil engineer(s). Additional lifts are installed in the same manner until the proper grade is achieved. Finally, equipment such as vibrating rollers for large areas or walk behind vibrating plates for pipe penetrations and edges should always be used.
Concrete jointing serves two basic purposes...to control the location of anticipated random slab cracking, and to aid in the esthetic appearance of architectural concrete. Below are the steps taken by Shaw & Sons to prepare for a concrete pour using the company's patented Speed Dowels for finely finished, expandable joints. Speed Dowels provide precise slip dowel alignment while greatly reducing cracking, spalling and displacement at construction joints.
A properly finished concrete project begins with intensive pre-planning and shop drawings reflect the exact dimensions and formwork of the mirrored project designed to withstand the loads incurred during concrete placement. This is where details, blockouts, and other necessary items, including form tie layout and types, are to be positioned. Next is hand-selecting forming materials. This procedure doesn’t cost nearly as much as the potential waste that can result by not doing is. Straight lumber for subframees will produce a finished product that is straight. Shaw & Sons always purchases new materials for each architectural job and will reuse forms only three times to ensure quality.
Up to three laminations (depending on the radius) are used on radius forms and fully gun-nailed to ensure that no delamination occurs during placing of concrete. Radius wallers are prescribed and precisely cut to match exact dimensions of the radius. Two top plates and two bottom plates are each laminated together, and are placed not greater than four feet o.c. horizontally.Forms should always be attached to a setting pad or footing, and pinned down three feet o.c. with drilled 16 penny nails. Adjustable braces ensure the wall tops will be in-line and plumb. All cast-in-place walls benefit from crack control reveals, and as previously described, can fall on four feet or modules of plywood joints.
This not only covers the joint with a detail feature, it also prevents bleed water leakage lines and will dictate feature, it also prevents bleed water leakage lines and will dictate a weakened plane for all wall to crack, preventing unsightly random cracks. If details are not used, forms should be removed as soon as possible and saw cuts should be kept wet for a minimum of seven days or a heavy coat of color cure should be applied.
The Richard Nixon Library & Birthplace, situated on nine rolling acres, offers visitors rare glimpses into the events, people and world that shaped, and were shaped by the 37th President of the United States.
The Library’s 52,000 square feet is now undergoing an almost 100% expansion with the new Katherine B. Loker Center scheduled to open in September of 2004. The Loker Center includes, along with the new Annenberg Court entrance pavilion and reception center, a full-size replica of the White House East Room, a 4,100 square-foot special exhibit gallery, and a large hall for private events and conference facilities.
Since its opening on July 20, 1990, the Nixon museum has attracted nearly 2.5 million visitors and created the most ambitious special exhibition and event programming of any Presidential Library in the nation. It was the President’s specific wish that the Library complex not be a sleepy, stodgy museum, but rather a vibrant, ever-changing landscape against which visitors, particularly young people, could learn more about the Presidency, our country and the world. As a “performing arts center for public affairs,” the library’s year-round programming features national policy conferences, study groups, town meetings, school editor forums, and a continual schedule of distinguished speakers and authors from government, politics, the media, and public affairs.
