ACI 330 R-08 – The Gold Standard of Concrete Parking Lot Design

When designing, constructing or proposing a concrete parking lot, there is just one standard that should be followed: ACI 330R-08 – “Guide for the Design and Construction of Concrete Parking Lots.”  PACA is offering a webinar that discusses the basis of the design guide, gives an overview of the guide’s sections, and most importantly, compares and reviews other commonly-used design procedures to that of ACI 330 R-08. We’re confident you will find ACI 330 R-09 is the best option for designing, constructing and testing of concrete parking lots. 

Engineers and architects earn one Professional Development Hour upon completion of this program. This seminar is registered with the American Institute of Architects Continuing Education Systems.

Single copies of ACI 330 R-08 (Guide for Design and Construction of Concrete Parking Lots) andACI 330.1-03 (Specification for Un-Reinforced Concrete Parking Lots) will be provided at no cost to each registering company.

Join us and learn more about concrete parking lot design!

Webinar: ACI 330 R-08 – The Gold Standard of Concrete Parking Lot Design
Date: Friday, April 29, 2011
Time: 11:00 AM – 12:00 PM EDT

After registering you will receive a confirmation email containing information about joining the Webinar.

For more information about the webinar, contact Ken Crank.

A Concrete Business Idea – Revisited

Seeing the Benefits 10 Years Later

Ten years ago, Muncy Homes covered its 15-acre headquarters and manufacturing site in Muncy, Pa., with a 7-inch thick layer of concrete. Meckley Concrete served as the contractor, while Centre Concrete supplied the product. Today, company officials are basking in the glow of sustained productivity gains.

“The site had never been paved before, and the company had been making do with a gravel surface since the firm was founded in 1972,” says Kim Rager, Muncy’s industrial resources representative.

“Every time we laid down new gravel, the weight of the tractor trailer cabs would quickly grind it into limestone dust,” continues Rager. “When it rained, the site turned to mud. When the sun came out, it became a dustbowl. On a hot, dry windy day, the neighbors would disappear behind clouds of dust.”

Muncy Homes fabricates modular housing and the alternately muddy and then dusty site made the company’s work infinitely more difficult.

Out of the 15-acre site, the firm’s buildings and structures only covered about five acres, leaving 10 acres that needed concrete pavement to make it easier to move, manipulate and load into trucks.

After operating on gravel for 30 years, company officials decided to renovate the site and pave it with concrete. “We did a lot of research on how other companies had done this,” Rager says. “We liked the way distribution centers — which have lots of heavy trucks on their sites — handled the problem.”

The engineering firm on the project developed a water runoff system that would operate underneath the concrete floor, drain water through a network of pipes and move it across a road into a retention pond.

The excavation produced a five acre pile of dirt across the road from the facility. Meckley staked out the excavated site, installed the forms and poured the slab in sections ranging in size from 100’ x 25’ to 100’ x 50’. The different sizes allowed the sections to fit themselves around the structures on the site.

As it turned out, the Muncy facility had a perfect base for pouring concrete and needed little in the way of additional gravel. “The land here sits on top of a prehistoric creek bed made of compacted sand and stone,” says Rager. “If you pour water on it, it just disappears — it goes right down through. The sand and stone layer probably goes down 20 feet and makes a perfect base for concrete. Meckley had to put down very little stone. Most of the site preparation involved leveling the surface.”

Despite the drainage system, some water will always remain under Muncy’s pavement. So the design of each concrete section included measures aimed at preventing the concrete from spalling or lifting up and settling back during the freeze thaw cycles common to the winters in this central Pennsylvania. location.

The Muncy installation employed doweled joints to do this. After pouring a concrete section, 15 one-inch holes were drilled into each side of the section every 18 inches. Thirty-inch long smooth dowel bars were inserted into each of the holes. When abutting concrete sections were poured, doweled joints connected the sections.

Such a design transfers the pressure of heavy loads to the entire slab and is recommended for pavements required to support heavy truck traffic characteristic of Muncy’s business. In addition, the doweled joints also allowed the slab to move slightly to the left and the right and up and down in response to changes in the ground below, related to freezing and thawing.

In specifying the project, Muncy and the engineers determined that the concrete would have to support 4,500 pounds per square inch (psi).

Muncy’s forklifts drove the extreme specification. “When one of our forklifts picks up a load, all of the weight is on the two front wheels,” explains Rager. “If the forklift picks up 10,000 pounds, all of that weight is on only about eight square inches of the forklift’s front wheels.”

During installation, concrete from each of the 100 pours required to cover the site was sampled and tested to ensure the consistency of the mix design specification.

Ten years after paving over the site, Muncy Homes officials say that the pavement has helped make the company more competitive and more productive.

“When our contractor customers visit our site, they compare us with our competitors that still work on chipped-up blacktop and dirt,” Rager says. “They see that we have saved money by not dragging mud into the homes they are buying from us. We believe that comes up when they sell to their customers.”

The pavement has also cut forklift maintenance. Dust and dirt increases wear and tear on main bearings and kingpins. With no more dirt to contend with, the forklifts stay up and running longer and require less time consuming maintenance when something does go wrong.

Inventory control is easier on concrete, continues Rager. The drainage problems on the dirt site required the forklift fleet to move components around after storms, which frequently flooded areas of the facility. The engineered drainage system has eliminated that problem and made it possible to assign certain spaces to certain products, just like any competent warehousing system.

“Everything about the project is positive,” Rager says. “After 10 years, we have no significant problems with the surface.”

Thanks to Mr. Michael Fickes who contributed this article.

Ask the Expert!

Q: I have heard the terms isolation joint and expansion joint used interchangeably, should they be?

A: ACI 330 RE-08 references the two terms in the following manner:

Concrete slabs should be separated from other structures or fixed objects within or abutting the paved area to offset the effects of expected differential horizontal and vertical movements. Isolation joints are used to isolate the pavement from these structures, such as light standard foundations, drop inlets, and buildings. They are full-depth, vertical joints usually filled with a compressible material. While sometimes referred to as expansion joints, they are rarely needed to accommodate concrete expansion. When they must be located in areas that encounter wheel and other loads, the pavement edges at the joint should be thickened by 20% or 2 in. (50 mm), whichever is greater.

Isolation joints are not recommended for routine use as regularly spaced joints. They are difficult to construct and maintain, provide no load transfer, and can be a source of pavement distress, distortion, and premature failure.

Isolation joints are not needed to accommodate expansion when contraction joints are properly spaced; their use should be limited to the role of isolating other structures or fixed objects. Designers are cautioned that wheel loads at isolation joints cause distresses similar to those at pavement free edges unless additional support is provided by features such as thickened pavement edges along the joint.