Concrete International
about ci careers register events calendar aci website search product guide   log in
Featured Articles
  April 1980  
Monolithic Concrete Wall Buildings - Methods, Construction, and Cost
Reprinted from ACI Proceedings V. 5, 1909, this is a description of one of the earliest site-cast, tilt-up wall panel construction projects undertaken. According to the article, the recent invention of a new mechanical method of erecting buildings of concrete without the use of forms or falsework, eliminating costly, cumbersome practices of erecting two wood walls to get one concrete wall is, itself, an invention of great moment and worldwide value especially in these days of scarce lumber and labor.The author describes the construction techniques used on numerous structures at Camp Logan, Ill., and Camp Perry, Ohio, using a massive site-cast, erection technique. Human labor and jacking procedures were used then compared to the mobile crane lifting techniques used today. This technique is compared to the modern day method in a discussion by Victor Leabu, which follows this reprint.

How to Add Texture, Color, and Beauty Using Chemical Retarders
There is no economical reason for tilt-up construction to look anything but bright, beautiful, and important. Varied architectural expression in tilt-up has evolved within the past decade. Creative architectural designs and textures have encouraged its use in areas never before thought possible. Chemical retarders have proved an economical means to produce exposed aggregate finishes that provide color, texture, and variety. Described are the various methods used in exposing aggregate in tilt-up wall panels. [Author]

Tilt-Up Approximate Constructlon Cost - 1979
Approximate costs are given for a typical 80,000 sq ft (7432 M2) tilt-up structure including lifting and bracing hardware, labor costs, and crane rental. The various costs are explained as well as insulation factors. Suggested design considerations are also shown. [Author]

Location of Inserts -Stresses in Panels
As the tilt-up panel is picked up it is subjected to bending that causes both compressive and tensile stresses which must be resisted by the concrete, rein-forcing steel, or a method of strongbacking that prevents the initial bending. Location of the lifting hardware is extremely important as well as the proper use of bond breakers to eliminate excess stresses or possible cracking of the panel during the pickup and erection stage. Recommended practices and field questions and answers are outlined in the article.

Implace Loads and Tiltmup Bearing Walls -A Design Approach
The PCA design aid method to analyze load-bearing -tilt- up walls for in-place loads is presented. This method is within the scope of Building Code Re-quirements for Reinforced Concrete (AC1 318077). Also, it takes into account factors such as slenderness ratios, reinforcement ratios, and secondary moments. [Author]

Computer Assisted Flexural Stress Analysis of Site-Cast Reinforced Concrete Tilt-Up up wall panels during erection
Equations are presented for the calculation of the rigging geometry when the panels are tilted from the horizontal to the vertical position. The equations are presented for typical two-high, three-high, and four-high cable riggings. These equations are nonlinear. Solutions to these equations are obtained by using numerical methods. An example is solved by a computer program written especially for execution from a time-sharing terminal. The computer program determines, for any angle of panel inclination, the geometry of the rigging, the forces in the cables, and the moments and flexural stresses in the panel. This ex. ample shows that the flexural stresses va& significantly as the panel is tilted into position.

Tilt-up Construction, Design Considerations - An Overview
Tilt-up concrete wall panel construction saves time and money. This method of construction originated in the early 1900s, gained acceptance and popularity after World War II, and is seen now in all parts of North America. Benefits of tilt-up construction accrue to the building owner, designer, and contractor. Wall finishes range from prestigious to utilitarian. High wall panels are constructed horizontally and quickly erected. Wall panels can support roof loads and eliminate beams and columns around the periphery of the building. Tilt-up is a solid concrete way to an excellent long term investment.

Concrete Mixes for Tilt-Up Wall Panels
Presents information related to concrete mix proportioning for the specifier, concrete producer, and contractor involved in construction of site precast or tilt-up wall panels. Concrete is classified as structural or architectural and the wall panel surface treatments obtainable with these concrete types are summarized. The various ingredients used in modern concrete (cement, fly ash, fine and coarse aggregate, chemical admixtures, and air-entraining agents) are discussed. Also discussed are concrete properties such as strength: air content, slump and accommodation of slump loss by job site slump adjustment, maximum water-cement ratio, fly ash substitution for cement, and sand-aggregate ratio. A procedure for proportioning structural and architectural concrete mixes to provide adequate strength for lifting wall panels cast under various ambient conditions is described.

Architectural Treatments for Tilt-Up Panels
Tilt-up is no longer an experimental system. Tilt-up offers the owner/designer the ability to esthetically blend his project into the local environment by utiliz-ing many locally available materials unique to that area. The key to successful architectural application is early investigation into finishes that blend into the surrounding environment. To achieve quality exterior finishes, many facets must be taken into considera-tion such as: properly prepared floor slab or areas where wall panels will be cast; test panels to assure consistency; and proper procedures for guaranteeing the desired finishes. [Author]


Advertising|Copyright|Privacy Policy|Home