UNIBUILD (USA)

A GOOD LOOK AT THE CONCRETE TILT-WALL BUILDING
UTILIZING THE UNIBUILD WALL PANEL

The conventional one story, tilt up building has a non-combustible and fire resistive rated, reinforced concrete bearing wall that is laterally supported at the foundation floor level and at the roof level. The walls of a tilt-wall building (TWB) are the heaviest and most expensive element of the shell. If the weight, connection requirements and labor-intensive casting on-site of this major element are reduced, the economics of the industrial buildings will change dramatically.

The main structural requirement of the exterior wall is that it must resist lateral loads from wind and earthquake forces. The conventional heavy tilt-up wall supports the lateral load as a wide vertical beam spanning from the floor to the roof. For today’s high bay buildings, the external walls must span 25’ to 30’, which requires the already heavy concrete wall to be thick enough to satisfy the span/depth ratio and the additional strength requirements of the higher spans. These heavy walls (approx. 94 lbs./sq. ft. for a 7 1/2” thick, 30 ft. high wall) contribute to the seismic forces in direct proportion to their mass, i.e. the level of seismic force goes up as the mass of the building is increased.

The UNIBUILD tilt-up panel, with its efficient 8’ span has a high aspect ration, for example, three-to-one for a 24’ high building. The light UNIBUILD panel will get its overturning capacity from the adjacent panels and anchorage to the footings and floor like a conventional shear wall. a finite element model will easily identify the shear load displacement between panels for the design of the panel-to-panel connection.

The UNIBUILD wall panel using structural lightweight concrete, will change the TWB significantly. The 8’ wide UNIBUILD wall handles the structural requirement very efficiently. It carries the lateral out-of-plane loads in the horizontal, short-span direction so the thickness need to be only 4” (min. 4” to satisfy the fire resisting requirements for exterior bearing walls). The vertical ribs of the UNIBUILD panel serve as vertical beams (carrying the horizontal 8’ span) spanning from the floor to the roof diaphragm. These vertical ribs at panel joists also serve as a column to support the roof. Since the most efficient roof system is a panelized 8’ module (from the 8’ x 4’ plywood sheet), the 8’ UNIBUILD wall panel optimizes the vertical load-carrying system as well as the lateral load-carrying system.

The most efficient foundation system for a tilt-up building is isolated pads or caissons, which vary in depth and diameter depending on the soil conditions. The ribs of adjacent UNIBUILD panels will share a pad directly under the centerline of the panel joint and the roof beam above.

The seismic force that the UNIBUILD panel must deal with in the in-plane direction is resisted by connections to the adjacent panels and by a reinforced concrete-grade beam that is part of the floor slab.

-/2

After this very efficient building envelope is enclosed using lightweight concrete for the UNIBUILD walls, we have a building that is less than 50% of the mass of a conventional TWB. The lighter UNIBUILD building is more compatible with its lightweight roof, which provides better performance during earthquakes, requires less roof-wall anchorage and less foundation work.

UNIBUILD - A DESIGNED BUILDING SYSTEM WHICH

. Reduces design requirements to wind loads.
. Reduces weight, connections, casting labor, foundation work and thickness.
. Optimizes vertical and lateral load-carrying system.
. An efficient 8’ span compatible with lightweight roofing systems.
. Provides better performance during earthquakes.
. Allows panel fabrication during site-work phase.
. Reduces construction crew time on-site.
. Reduces skilled labor cost.
. Panel material greatly reduces water penetration and absorption.
. Panel material improves fire resistance.
. Panel material increases insulation quality and reduces energy cost.
. Allows lower cost panel construction on confined jobs.
. Reduces time of construction and cost of loan interest.
. Transports by conventional truck or rail, stacked horizontally.
. Can dramatically reduce the economics of construction.

UNIBUILD - WARRANTS YOUR CONSIDERATION

(By Breiholz Qazi Engineering, Inc. Civil and Structural Engineering, Seismic Hazard Reduction, Architecture).- California, USA.

UNIBUILD is the Registered Trademark of UNIBUILD PTY. LTD. AUSTRALIA.

(REF:USA-05)