Trends Summer 2011 - Page 8

familiar with the process before moving forward . “ The City was looking for an alternative solution that would be both cost-effective and constructible ,” Jacobsen said , adding it was also important that scour protection remain buried to replicate a natural stream bed under the bridge .
Despite initial skepticism , the process went smoothly . The riprap installation required careful maneuvering of a concrete pump truck and extendable boom under the bridge to place the grout properly . Ayres Associates oversaw the installation to see that it was achieved according to plan .
Danny Tezak , president of Tezak Heavy Equipment , the project ’ s contractor , said the partially grouted riprap was easier to install than traditional large boulders . “ I think the ( partially grouted riprap ) will have its place ,” he said , such as in confined spaces with tight clearances . “ The concept is very good .”
Tezak is the first contractor in the United States to use this innovative grouting technique , and Pennington praised their willingness to tackle the job . “ Tezak showed a lot of patience and diligence throughout the construction process , resulting in a high-quality project ,” he said .
Ayres Associates adapted the partially grouted riprap method to United States engineering practices as part of ongoing research for the Federal Highway Administration . The process was published in September 2009 as an approved countermeasure for protecting bridge piers against scour .
Construction of the riprap , grade control structure , and bank stabilization measures were completed without affecting the public . The pedestrian trail along the river remained open during construction so the link to the neighboring high school and surrounding areas remained intact , and the bridge remained open to traffic . Construction was sequenced so Sand Creek flows were diverted to one side of the channel while riprap and grout were installed on the other side . This allowed construction to occur in dry conditions to avoid environmental and construction issues commonly associated with placing grout in flowing water .
The improvements will increase public safety by protecting the bridge and surrounding areas in case of flooding . “ This was a total team effort ,” Pennington said . “ The efforts between the City stormwater division , the City bridge department , the batch ( concrete ) plant , Tezak , and Ayres Associates went very well and resulted in an outstanding product enhancing the community ’ s safety .”
If conventional materials and design methods had been used for the riprap design , protection against the 50-year flood would have cost the City approximately $ 140,000 . The partially grouted riprap alternative cost $ 47,000 and provides protection against a 500-year flood .
Ayres Associates exceeded the City ’ s expectations , Jacobsen said , by presenting an innovative approach resulting in an aesthetically pleasing and sustainable solution that did not disrupt traffic during construction .
“ We hired Ayres Associates for its expertise in channel restoration and bridge scour countermeasures , and they did not disappoint ,” Jacobsen said . “ The project was completed on time , and Ayres Associates ’ design saved us considerable money while providing a better solution to a complex problem .”
8│TRENDS
familiar with the process before moving forward. “The City was looking for an alternative solution that would be both cost-effective and constructible,” Jacobsen said, adding it was also important that scour protection remain buried to replicate a natural stream bed under the bridge. Despite initial skepticism, the process went smoothly. The riprap installation required careful maneuvering of a concrete pump truck and extendable boom under the bridge to place the grout properly. Ayres Associates oversaw the installation to see that it was achieved according to plan. Danny Tezak, president of Tezak Heavy Equipment, the project’s contractor, said the partially grouted riprap was easier to install than traditional large boulders. “I think the (partially grouted riprap) will have its place,” he said, such as in confined spaces with tight clearances. “The concept is very good.” Tezak is the first contractor in the United States to use this innovative grouting technique, and Pennington praised their willingness to tackle the job. “Tezak showed a lot of patience and diligence throughout the construction process, resulting in a high-quality project,” he said. Ayres Associates adapted the partially grouted riprap method to United States engineering practices as part of ongoing research for the Federal Highway Administration. The process was published in September 2009 as an approved countermeasure for protecting bridge piers against scour. Construction of the riprap, grade control structure, and bank stabilization measures were completed without affecting the public. The pedestrian trail along the river remained open during 8│TRENDS construction so the link to the neighboring high school and surrounding areas remained intact, and the bridge remained open to traffic. Construction was sequenced so Sand Creek flows were diverted to one side of the channel while riprap and grout were installed on the other side. This allowed construction to occur in dry conditions to avoid environmental and construction issues commonly associated with placing grout in flowing water. The improvements will increase public safety by protecting the bridge and surrounding areas in case of flooding. “This was a total team effort,” Pennington said. “The efforts between the City stormwater division, the City bridge department, the batch (concrete) plant, Tezak, and Ay ɕ́ͽѕ)ݕЁٕݕɕձѕ)хɽՍЁѡ)չéͅ今t($%ٕѥѕɥ́)ͥѡ͕́)ѡɥɅͥɽѕѥ)ѡ啅ȁݽձٔ)ѡ 䁅ɽ᥵ѕ䀐)Qѥ䁝ɽѕɥɅ)ѕɹѥٔЀܰ)ɽ٥́ɽѕѥЁ(啅ȁ($ɕ́ͽѕ́ፕѡ) éхѥ̰)͕ͅ)ɕ͕ѥمѥٔ)ɽɕձѥ)ѡѥͥ)хͽѥѡЁ)ЁɅɥՍѥ($+q]ɕɕ́ͽѕ)ȁ́ѥ͔)ɕѽɅѥɥ͍)չѕɵɕ̰ѡ䁑)ͅгu)͕ͅqQ)ɽЁ݅́ѕѥ)ɕ́ͽѕϊdٕͥͅ)ͥɅݡ)ɽ٥ѕȁͽѥѼ)ɽt((