Earthquakes and Building Codes

Given the recent earthquakes in Turkey, Chile, and Haiti, our hearts and thoughts go out to each country.

Since the Chile earthquake was an 8.8 magnitude and the Haiti earthquake was a 7.0 magnitude common sense would dictate the Chilean earthquake to cause more devastation; however, the exact opposite has been observed. The reasons are simple:

1. Location: Chile earthquake was located 21 miles underground and in a relatively unpopulated area while Haiti’s quake was shallower at only 8 miles beneath the surface and very close to Port-au-Prince.

2. Quality of Seismic Codes: Chile, with a recent history of major quakes, has adopted quality seismic codes and construction practices while Haiti does not have a seismic code. It is often said that earthquakes alone do not cause devastation; it requires poorly constructed structures to be susceptible to the earthquake motions.

The recent earthquakes (including the 9.3 Indian Ocean quake in 2004) appear to be consistent with the observed 50-year cycle of seismic activity. The last cycle included the 9.5 and 9.2 magnitude quakes near Valdivia and Prince William Sound, respectively. It is not a case of ‘if’ but ‘when’ the next big quake will occur. Whereas the Haiti quake was a wake-up call for building codes around the world, the Chile quake was a practical test of modern seismic codes.

The “Suite” Comfort of Concrete

This all-concrete building, including a stucco exterior, incorporates roofs, floors, interior and exterior walls made from autoclaved aerated concrete (AAC) panels and blocks. AAC is a lightweight, cement-based material that has been popular in Europe for more than 60 years. Its success in the U.S. during the past few decades has been more limited, but material producers see opportunity for growing the market with today’s focus on sustainable development. The product is energy efficient and can contain recycled material, both of which are appealing from a green perspective. More.

Quick Concrete Construction Re-Opens Florida Hotel

When a 2008 New Year’s Eve fire destroyed the main building of the Cheeca Lodge and Spa in the Florida Keys, the owners rebuilt the historic hotel in a matter of months with precast-concrete modules. More.

Building Universe Versus Building Code

Buildings of moderate size and height, as the two examples presented above, represent a large percentage of those being designed and built every year. All structures whether low-rise, moderate-rise or ultra-tall skyscraper, have to be designed according to the requirements of the local adopted building code. With the advancement in material technology, introduction of new concepts and structural innovation, the code has increased in complexity and size. In 1956 the ACI 318 Code was printed in 73 small-size pages; by 2008, the ACI 318 Building Code Requirements for Structural Concrete and Commentary contained more than 460 large-size pages. Engineers have to become familiar with a substantial amount of technical material in order to design a concrete building.

In the popular PCA publication known as Simplified Design the information in the code is condensed into a step-by-step procedure for the building and member design. The formulae and language avoid complicated legal terminology without changing the spirit of the code. The book is written as a time-saving design aid; to simplify design procedures using the provisions of ACI 318 for reinforced concrete buildings of moderate size and height.

ACI/PCA Simplified Design of Reinforced Concrete Buildings of Moderate Size
One-day seminar sponsored jointly by the Portland Cement Association and ACI

Increase your design efficiency and reduce the time it takes to design small to moderate size buildings by applying the design procedures that you will learn at this seminar in accordance with ACI 318-08, IBC 2009, and ASCE 7-05. More information and registration.

Reinforced Concrete Design
Two-day seminar sponsored jointly by the Portland Cement Association and ACI

More information and registration.

Entries Now Being Accepted for 2010 Sustainable Leadership Awards

PCA announces a call for entries for the 2010 Sustainable Leadership Awards. Now in its third year, the Sustainable Leadership Awards program recognizes public officials that employ the use of concrete and cement-based products for sustainable, long-lasting benefits. More information and access to the nomination form.

First Phase of Green Construction Code Completed

As part of a collaborative effort, the International Code Council (ICC) is developing a new set of green codes under the multi-year initiative called “IgCC: Safe and Sustainable by the Book.” PCA participated on the ICC committee that developed this draft IgCC. The first public review became available on March 15, 2010 (from iccsafe.org). Initial and final action hearings are scheduled for spring and fall of 2011, respectively, with publication of the first edition anticipated in 2012.

Concrete Sustainability Conference

Join the National Ready Mixed Concrete Association and the School of Sustainable Engineering and the Built Environment at Arizona State University for the 2010 Concrete Sustainability Conference, April 13-15, in Tempe, Ariz. More.

This guide, which includes a foreword by Dr. Gene Corley, provides structural engineers with a practical treatment of the design of cast-in-place reinforced concrete structures to resist the effects of blast loads. Readers will be able to understand the principles of blast-resistant design, determine the kind and degree of resistance a structure needs, and specify the materials and details required to provide it. Guidelines are provided for detailing requirements for blast resistance and detailing philosophy and reinforcement splicing are introduced for columns, beams, slabs, walls and joints. Numerical design examples are provided showing the detailed design of reinforced concrete elements under blast loading. The guide also includes a chapter devoted to GSA and DoD design methods to protect structures against progressive collapse. More information and purchase.

More resources on design for security.

spSlab and spBeam Updates Released

Formerly pcaSlab and pcaBeam, version 3.10 of these StructurePoint programs released new improvements geared towards optimizing design and simpler detailing. Moment distribution factors refined in this release provide critical improvements for the analysis and economical design of concrete floor systems. Updates targeted combinations of unique design conditions resulting in congestion of reinforcement over supports, wall supported floor slabs and slab band systems with transverse beams. Review the program technical manual for details and to learn more about spSlab and spBeam features.

More about StructurePoint’s reinforced concrete analysis and design software.

Annual Building Professors' Seminar
August 2-4, Skokie, Ill.

In an effort to keep the concrete industry in touch with university professors of civil, structural, and architectural engineering, the Concrete Reinforcing Steel Institute (CRSI), the National Ready Mixed Concrete Association (NRMCA), the Portland Cement Association (PCA), the Precast/Prestressed Concrete Institute (PCI), and the Post-Tensioning Institute (PTI) co-sponsor an annual Building Professors' Workshop. Since 1992, the seminar has been held every summer at PCA's Skokie, Ill., headquarters. Sponsored by regional cement and concrete promotion groups, professors from around the U.S. travel to Skokie to attend this three-day workshop. More.

Engineering Today’s Play into Tomorrow’s Careers
To celebrate National Engineers’ Week, the annual DuPage Area Engineers Week Expo was held on February 20 at the Illinois Institute of Technology and attended by more than 1,200 students and parents. The Engineers Week events provide students the opportunity to experience and explore the many fields of engineering through a series of interactive displays and presentations. At the Engineering Expo, PCA Director of Engineered Buildings, Larry Novak, presented "High-Rise Building Design: Shake, Rattle & Roll!” This high energy interactive and educational program included presentations on the Burj Dubai Tower, the world’s tallest structure, and the Trump Tower, Chicago. More.

• American Concrete Institute Spring Convention
March 21 – 25, Chicago, Ill.

• University of Illinois 11th Annual Structural Engineering Conference
April 8, Champaign, Ill.

• 2010 Structures Congress
May 12 – 15, Orlando, Fla.
Ina session titled “Tanks and Tower,” Mahmoud Kamara of PCA will offer a presentation on design of circular concrete tanks.