Concrete International
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Featured Articles
  September 2015  
 
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Physical Models in the Reinforced Concrete Design Classroom
An overview is presented of various physical demonstration tools intended to supplement lectures in topic areas that students consistently identify as being troublesome. The article describes the design, fabrication, and implementation of classroom models to help explain flexural behavior and detailing of beams, slabs, and frame systems.

IDM for Cast-in-Place Concrete
In 2014, ACI Committee 131, Building Information Modeling of Concrete Structures, published its first document: “Information Delivery Manual (IDM) for Cast-in-Place Concrete (ACI 131.1R-14).” The report was created through a collaboration between concrete contractors, reinforcing bar fabricators, software vendors, engineers, ready mixed concrete suppliers, and industry organizations. The IDM summarizes the cast-in-place concrete industry by defining design and construction processes and information flow required by these processes.

Shored/Reshored Construction of Flat Plates
Flat plates are usually constructed using a single level of shores (forms) supporting the freshly placed concrete. Shored construction accumulates load to the lowest (oldest) plate in the shored sequence, while shored/reshored construction applies the load to the upper (youngest) plate in the system. Historical shoring analyses are reviewed and the results of a parametric analysis of the effect of reshore stiffness are presented. Based on the analyses, factors are provided for calculation of the required strength of supporting flat plates in buildings constructed using a single level of shores and multiple levels of elastic reshores.

Drone Companies Set Sights on Construction Industry
The use of unmanned aerial vehicles could soon be the status quo for construction companies around the world. The devices allow rapid and efficient inspection and mapping of construction sites. Low-level aerial photography has adequate resolution for generation of accurate three-dimensional models. While the technical possibilities are unlimited for using these vehicles in construction, major hindrances are created by regulatory constraints.

The Future of 3-D Modeling for Concrete Contractors
Building Information Modeling (BIM) has only been in use for a decade. BIM has changed from a visualization tool used by architects to communicate design ideas to infiltrating every discipline in the construction industry. Nowhere is that more evident than the concrete industry, where concrete contractors have proven that building 3-D project models leads to better structures with less waste, lower contingencies, and more efficiency. New technologies and practices are already growing in use, and others are on the way.

Knowledge to Practice: ACI Foundation

The International Parking Institute 2015 Awards of Excellence

Concrete Q&A: Grade 40 No. 11 Reinforcing Bars
Q. I’m evaluating an existing reinforced concrete shear wall parking structure located in Southern California. It was reportedly designed and built in the early 1980s. The general notes state that the dowels for the wall-to-foundation connections are Grade 40 reinforcing bars, and the wall sections show that the dowels are No. 11 bars. Could the bars be Grade 40? I’m questioning if a No. 11 reinforcing bar could be manufactured in Grade 40 in the early 1980s. My train of thought is that even though the engineers specified Grade 40, only Grade 60 could be provided for such a size and therefore the higher grade bar was used.

Concrete International September 2015 No. 9 Complete Issue

 


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