This paper describes the arch design process, which included both two and three dimensional finite-element analysis for the arch cross section design, and to check the effect of differential longitudinal loading and foundation conditions. The effect of many alternative ground improvement options was considered, in order to optimise the foundation design. The final design was developed after the award of the contract and used three different options, depending on the ground and weather conditions at the time of construction. The following information is presented in the paper:

• Comparison of bending moments and forces in the adopted arch profile with alternative profiles.
• Comparison of foundation bending moments and forces for different raft cross-sections and foundation treatments.
• Comparison of alternative analysis methods for the raft foundations
• Comparison of settlement analysis results with analyses carried out by the project primary designers (SMEC Australia).
Doug Jenkins, Interactive Design Services Pty Ltd, Chris Lawson, Reinforced Earth Pty. Ltd.

PennDOT had a challenge on their hands, as they attempted to balance three key fac-tors while trying to figure out which alternative was the best solution for the cost. They wanted to match the shape of the existing culvert they were tying into, minimize the impacts to the surrounding community, as well as accommo-date the numerous existing pipelines that have been added to the culvert throughout the years.

After examining various alternatives, engi-neers at PennDOT and Oldcastle Precast, Inc. developed a simple solution to the problem while allowing for a quick installation. PennDOT elected to use a 48-inch x76-inch horizontal el-liptical reinforced concrete pipe (HERCP) with flared end sections on both sides of the roadway in lieu of a precast box culvert or other meods. This would allow for a four to six week con-struction schedule and the best product for the money spent. HRI, Inc. of Bloomsburg, PA was selected by PennDOT to complete the proj-ect and Oldcastle of Farmingdale, NJ provided the elliptical pipeline and flared end sections.

Eleven existing pipelines (five pipelines on the northbound side and six on the southbound side) of various sizes and types had been tied into the existing culvert at various times, providing a chal-lenge for construction. These pipes ranged in size and material from 8-inch diameter ductile iron to 18-inch diameter reinforced concrete, and were aligned at different inverts and angles. The exact tie-in location of these lines needed to be deter-mined, so a laying schedule was developed. Each pipe could then be numbered and pre-cut holes positioned to allow for the existing lines to simply be mortared into place. The pipe was assembled by Oldcastle prior to shipment to ensure the ac-curacy of the hole placement and joint al

Winner of the 2006 Outstanding Shotcrete Project Award given by the American Shotcrete Association (ASA)
This bridge is the focal point of this upscale, lake orientated community. Shotcrete was used to construct the entire bridge from the footings to the handrail base. The “stacked stone” look was accomplished by using a conventional form liner and then hand painted. {source}

Bottomless arch culvert installations also have the low profile advantage of an ellipse type culvert. Bottomless arch structures may be used at sites with slopes ranging fro 0% to 6%, but bottom materials inside the culvert should include boulders large enough to withstand current flows. On sites with slopes from 3% to 6% this means utilizing D90* size rock (D90 size material refers to the largest 10% of naturally occurring boulders in the stream). In some installations special preparations (like rock placement) are needed to address possible scour erosion of the stream bed that could undermine the culvert footing.

In this photo, the flange footing type, bottomless arch culvert is being lowered onto the prepared streambed. Note the placement of D90 (or larger) boulders in the channel to provide resting places for migrating fish. The term D90 refers to the size of the boulders in the vicinity of the crossing. The size of a D90 boulder is equal to the average of the largest 10% of the boulders in the stream bed.

This corrugated metal, bottomless arch culvert is provided with a metal flange footing and rests on a cement base. It is a highly functional installation, does a great job of maintaining fish habitat and is competitive in price with a round culvert installation. {source}

TechSpan® is the most reliable, cost-effective precast concrete arch system available for the construction or replacement of culverts and bridges.

Advanced design procedures and unique fabrication capabilities provide the most efficient use of concrete and reinforcing steel. Unlike most alternative systems, efficiency and economy of design increase progressively as the embankment height over the crest increases. Construction of TechSpan is simple, rapid and predictable with small crews and conventional equipment.

Name : TechSpan
by : The Reinforced Earth Company