CA4PRS Implementation Project
for Rapid Rehabilitation
CA4PRS is a schedule and traffic analysis software tool that helps planners and designers select effective, economical pavement rehabilitation strategies. The software's scheduling module estimates highway project duration (total number of closures), incorporating alternative strategies for pavement designs, lane-closure tactics, and contractor logistics. Its traffic module quantifies the impact of construction work zone closures on the traveling public in terms of road user cost and time spent in queue.
The use of CA4PRS is especially beneficial when it is used during the planning and design stages of highway project development in order to balance schedule (construction production), inconvenience (traffic delay), and affordability (agency budget). By performing this optimization, the agency can reduce construction schedules, providing savings in personnel and construction costs, and can reduce overall road user delay caused by construction closures. CA4PRS is currently fully functional for a wide variety of pavement rehabilitation and maintenance strategies for asphalt and concrete pavements, including traffic and cost analysis. Caltrans has an unlimited license to use CA4PRS on state computers. For the last few years, more than 700 district engineers and technical personnel have been trained, and CA4PRS has been used on a few projects in the districts.
Caltrans, which oversees a 82,000 lane-km state highway system, also began implementing its Long-Life Pavement Rehabilitation Strategies (LLPRS) program in 1998. The goal of the LLPRS program is to rebuild approximately 2,800 lane-km of high volume urban freeway with pavements that are designed to last more than thirty years with minimal maintenance. The LLPRS program will reduce the need for future repair projects and ultimately save public resources for future generations of road users. LLPRS candidate projects were selected from among highways that experience minimum volume demands of 150,000 Average Daily Traffic (ADT) or 15,000 Average Daily Truck Traffic, and that have poor structural pavement condition and ride quality. Most LLPRS candidate sections are Portland Cement Concrete (PCC) pavements on interstate freeways in urban networks, 80 percent of which are within the Los Angeles Basin, and 15 percent of which are in the San Francisco Bay Area. CA4PRS has also been used on a number of these LLPRS projects.
Status Summary of the Implementation Projects
|Route||Location||Type||Project Cost||Estimated Cost Savings*||Length||Year Begin Const.||Implementation Status**|
|I-5||D10, Stockton||CRCP Rehab||$45M||-||3 miles||2012||Adopted|
|I-5||D2, Redding||AC Rehab||$50M||-||14 miles||2011||Not Adopted|
|I-5||D3, Sacramento||AC Rehab||$88M||$15M||17 miles||2011||Partially Adopted|
|I-80||D3, Sacramento||PCC Rehab||$92M||$5M||9 miles||2011||Partially Adopted|
|I-5||D3, Yolo/Colusa||AC CAPM||$25M||-||24 miles||2010||Not Adopted|
|SR-99||D3, Elk Grove||AC CAPM||$21M||$3.5M||14 miles||2010||Not Adopted|
|I-680||D4, San Ramon||Rehab||$70M||$1M||12miles||2010||Partially Adopted|
|US-101||D1, Ukiah||PCC CAPM||$19M||$2M||6 miles||2010||Not Adopted|
|US-101||D4, San Jose||AC CAPM||$47M||$3M||7 miles||2009||Partially Adopted|
|I-15||D8, Ontario||PCC Rehab||$59M||$5M||8 miles||2009||Partially Adopted|
|I-280||D4, Santa Clara||PCC CAPM||$20M||$2M||6 miles||2009||Not Adopted|
|I-15||D8, Devore-II||PCC Rehab||$24M||$4M||5 miles||2007||Adopted|
|I-15||D8, Devore-I||PCC Rehab||$16M||8M||3 miles||2005||Adopted|
|I-710||D7, Long Beach||AC Rehab||$17M||$1M||5 miles||2003||Adopted|
|I-10||D7, Pomona||AC Rehab||$16M||$0.3M||1 mile||2000||Partially Adopted|
* Estimated cost savings by adopting the alternatives recommended by CA4PRS assessment as compared with project initial design.
** Adopted, partially adopted, or not adopted: the project team decided fully, partially, or not to implement CA4PRS recommendations into the project considering other circumstances and constraints.
Details of the Implementation Projects
Project Scope: The I-680 project is a large-scale highway renewal project to resurface or rebuild an approximately 12.6-mile stretch of existing concrete pavement on an urban corridor near Walnut Creek (about 30 mile east of San Francisco). In terms of the project scope, about half of the project boundary (in the south; from PM 0.0 to 7.5) is designed for concrete pavement rehabilitation mainly with pre-cast panels, whereas the remaining half of the project area (in the north: from PM 7.5 to 14.8) is designed for AC overlay surfacing with Crack-Seat and Overlay method. The number of lanes varies between 4 and 5 lanes per direction (including one HOV lane on the median), and all lanes (mainline and shoulders) will receive the rehabilitation treatment. The Average Annual Daily Traffic (AADT) along this stretch of highway is approximately 180,000 (both directions). Truck percentage is about 6 percent. The estimated overall project duration is about 25 months over 3 construction seasons, expected to start construction in Fall 2010.
Work Schedules: Various, somewhat complicated, types of construction work shift schedules will be adopted on the I-680 project, based upon a consideration of lane closure schemes, rehabilitation scope (renewal design), and construction locations, while attempting to minimize traffic disruption through the work-zone.
- Nighttime (8-hour) Work (with partial lane closures)
- Mill (cold-plane) existing AC pavement and place new AC pavement on HOV lanes and shoulders for a total of about 45 lane-miles
- Crack-seat (basically break) existing concrete (PCC) pavement and place AC overlay pavement for a total of about 60 lane-miles
- Daytime (8-10 hour) Works (with shifted traffic; no lane closures) for a total of about 20 lane-miles to remove existing concrete pavements and place new base and new concrete (28-day curing-time JPCP) pavements.
- Extended Weekend (33-hour) Work (with dynamic lane closures) for a total of about 10 lane-miles to remove existing concrete pavements and place new base and pre-cast concrete panels (with or without post-tensioning).
The project is designed to adopt so-called "dynamic lane configuration" for the 33-hour weekend closures to most efficiently accommodate work-zone traffic. The project TMP requires the contractor to change the lane closure configuration 8 times over the 33-hour extended weekend closure, starting with 4 lanes open (4L) per direction through the work zone, then implementing lane openings of 3L, 2L, 1L, 2L, 3L, 2L, 1L, and 4 Lanes, using Quick-change Moveable Concrete Barriers. These dynamic lane configuration changes will require the contractor's crew to work under very tight work-zone space and schedule constraints.
Pre-Cast Rehabilitation: For pre-cast rehabilitation work, two lane closure (work-shift) alternatives were compared for the transportation management plan (TMP) analysis: (1) 24 x 33 hour weekend closures (Sat 8 pm to Mon 5 am), and (2) 291 x 8 hours weeknight closures (9 pm-5 am). Based on this comparison, the 24 times of 33-hour extended weekend closures construction schedule was determined to achieve more productivity, which will reduce the overall project duration to half, compared to the conventional nighttime construction closure construction. This is a Design-Bid-Build contract with Incentives/Disincentives. Major incentives will be associated with the total number of 33-hour weekend closures, with incentive bonus awarded for each weekend closure reduction up to the total incentive amount.
Project Scope The I-15 Ontario Project is a highway renewal project to rebuild an approximately 5-mile stretch of long-life concrete pavement on an urban corridor (about 50 miles east of LA). The project includes various types of innovative construction, such as "pre-cast concrete" and "rapid-strength concrete." The primary goals of this project are to provide long-lasting pavement (30+ years), to induce minimum work-zone impact on road users, and to achieve maximum construction productivity. FHWA granted $5 million to this project through its Highways for LIFE program to support the project's goals and the innovative features. Overall project duration is about 20 months (410 working days), starting in April 2009 and finishing in November 2010. Project Cost is estimated at $52M (Engineer's Estimate was $68M). The Average Annual Daily Traffic (AADT) along this stretch of highway is approximately 200,000 (both directions). Truck percentage is about 10 percent. The total number of lanes on this portion of I-15 varies between 4 and 5 lanes per direction, with between 2 and 3 lanes being rebuilt in each direction.
The project includes multiple stages of work. The first stage involved bridge widening and median paving. The second stage shifts southbound traffic toward the median while pavement in the outer southbound lanes is rehabilitated. After some minor adjustments in the median, the next stage shifts the northbound lanes toward the median in a similar manner to rehabilitate the outer northbound lanes. The final stage of work places a permanent concrete barrier along the median.
Work Schedules The project requires various types of construction operations, such as conventional daytime-shift continuous work, 55-hour extended weekend work, and traditional nighttime work, depending on the specific project element locations and lane closure schemes. For example, about 27 repeated weekend closures with non-stop construction are required, primarily for interchange ramps and freeway-to-freeway connector areas, with full traffic closure providing better contractor access. The pre-construction analysis indicated that 27 extended weekend construction work closures would allow the completion of work equivalent to about 3-4 years of repeated nighttime work closures. Time savings achieved by using extended weekend closures (versus all nighttime closures) was estimated to be almost 3 years, and of course, results in a much better product than what nighttime closures would have achieved. In other words, the project is taking a little over 2 years to complete instead of 5 years, due to the use of extended weekend closures, median paving, and shifting traffic during construction. The 55 hr weekend closures ultimately increase productivity, safety, and reduce contract time to deliver the project. On the other hand, the southern area of the project boundary is designed for approximately 100 nighttime shifts using rapid-strength concrete (4 hour curing-time concrete mix) due to limited space for traffic detours. Other mainline areas are designed for conventional daytime shift-work behind concrete barriers with traffic detoured to temporarily widened median areas.
Contract Type This is a Design-Bid-Build contract. The contract has Incentives/Disincentives clauses that have a total budgeted amount of $0.9M dollars of incentive. The incentive is used to increase the contractor's construction schedule awareness to become innovative and to increase productivity efficiency so the number of 55-hour weekend closures is reduced. The incentive bonus of $150k is awarded for each weekend closure eliminated or reduced below the minimum expected 27 closures for the extended 55-hr weekend closures. The total maximum incentive is limited up to $0.9M for the contract.
|Video Clip: I-15 Ontario Pre-cast Concrete Pavement Construction|
Project Scope For the rehabilitation of a 4.5-km stretch of two badly damaged concrete truck lanes on Interstate 15 (I-15) near the city of Devore, Caltrans chose the "Rapid-Rehab" strategy. In this I-15 Devore project the two concrete truck lanes were successfully rebuilt in only two nine-days extended closures utilizing counter-flow traffic and around-the-clock operations. The pre construction schedule estimate projected that this project would take ten months using traditional nighttime closures. Instead, rebuilding took about nineteen days (with each extended closure for one roadbed lasting roughly nine days). The advantages of using this method of fast-track reconstruction included a significantly shorter period of disruption for the traveling public, new pavement with a thirty year life expectancy, increased safety for motorists and workers, and a 25 percent reduction ($6 million) in construction costs, compared with traditional repeated nighttime closures.
Innovative Features Innovations adopted for this groundbreaking "Rapid Rehab" project included:
- Automated Work Zone Information Systems (AWIS) to update travelers with real-time work zone travel information
- The Quickchange Moveable Barrier (QMB) System (by Barrier Systems Inc.), which provided dynamic lane configuration to minimize traffic disruption
- A rapid-strength concrete mix that made it possible to open the project to traffic twelve hours after its placement while still allowing for slip-form paving
- Web-based information systems for disseminating project updates and surveying public perception
- Incentive/disincentive provisions to encourage the contractor to complete the closures on time
- A multifaceted outreach program to gain public support and to help road users divert to alternate routes and adjust their daily commuting pattern
- A simulation-based framework incorporating macro- and microscopic simulation tools to analyze traffic performance through the construction work zone
The use of innovative technologies and intensive public outreach efforts reduced traffic demand by 20 percent and the maximum peak-hour delay by 50 percent of what was initially expected. Four-hundred respondents to two web surveys on the project web site showed a dramatic change in perception of the fast-track construction strategies, swinging from strong initial objection to support for future fast-track projects.
|Construction Video Clip|
|Traffic Simulation Video Clip|
|I-15 Devore Photos|
Project Scope Caltrans has successfully rebuilt a 4.4-km stretch of Interstate 710 (I-710) in Long Beach, which carries more truck traffic than any other route in the state. This long-life asphalt concrete (AC) pavement rehabilitation project -- which occurred during the summer of 2003 and in which either 230 mm of AC overlay or 325 mm of full-depth AC replacement were applied during eight repeated 55-hour weekend closures -- took a fast-track construction approach that included around-the-clock (24/7) operations. The project proved that fast-track rehabilitation with 55-hour weekend closures is effective to drastically shortening overall construction time and lessening the negative effects of construction in an urban area. The project also proved that AC pavement designed to provide a 30+ year design life can be constructed in a series of weekend closures even on the most heavily loaded truck route in the state.
|Construction Video Clip|
|Traffic Simulation Video Clip|
|I-710 Long Beach Photos|
Project Scope In February 2000, a 20 lane-km rehabilitation project on the Interstate 10 (I-10) near Los Angeles was successfully completed. Fast setting hydraulic cement concrete (FSHCC) was applied because it reaches traffic opening strength only in four hours after its placement. The project required one weekend closure to complete 2.8 lane-km and repeated 7- and 10-hour nighttime closures for the remaining distance. The rehabilitation project consisted of replacing the 230 mm concrete slab with new concrete, dowels, and tie bars. The contractor used a concurrent working method in which demolition and concrete paving occurred simultaneously and only a single lane was removed and replaced.
The delivery and discharge of concrete controlled the overall progress. The 55-hour weekend closure proceeded at a 54 percent faster rate than the average of nighttime closures, as measured by number of slabs replaced per hour. A comprehensive traffic management strategy helped to reduce the volume of traffic during the weekend closure and minimize the traffic delay through the construction work zone.
|I-10 Construction Photos|