Fascia beams with vertical faceprojections are 2.45 ft deeper providingconfinement for the roadbed ballast anda base for the balustrade railings. Photo:PBS&J, an Atkins company.Placement of balustrade railings onbeam face projections and architecturalprecast concrete pilasters on the edges ofbents 2, 3, and 4. Photo: City of RanchoCucamonga.PrefabricationSupports ScheduleGirders, pilasters, and balustrade railingswere prefabricated off site utilizingreusable forms to avoid the need forhandling intricate forming details inthe field. Prefabricating these units alsoaccelerated construction, which furtherreduced costs.Precast, Post-tensioned<strong>Concrete</strong> Arched Girders<strong>The</strong> four-span, 172-ft-long bridge is 39ft 1½ in. wide with 44 arched precastconcrete box girders; <strong>11</strong> in each span.<strong>The</strong>se are simply supported at the piersupports and the abutments and areplaced edge to edge, allowing a ¾-in.-wide joint. <strong>The</strong> span lengths were 53ft in the center spans over the roadwayand 33 ft in the approach spans over thesidewalks. <strong>The</strong> design utilized large girderunits with depths of 9.88 ft and 12.33 ftand weighing up to 70 tons. <strong>The</strong> girderswere designed to be cast on their sidesand post-tensioned after removal fromthe forms and being set upright. In orderto achieve a uniform appearance, thegirders were cast so the exposed facewas down-in-form to achieve a more<strong>The</strong> City of Rancho Cucamonga has abold new landmark—a precast concretebridge that compliments the San GabrielMountain range while welcoming visitorsto the town center. Photo: City of RanchoCucamonga.uniform distribution of aggregate alongthat face. <strong>The</strong> design compressivestrength of the girder concrete was 6000psi. Since the width of the units wasapproximately 3.5 ft, casting sidewayshad the further benefit of reducingformwork costs. <strong>The</strong> use of precastelements accelerated the constructionschedule. All girders were erected in just4 days.Piers and PilastersFlared cast-in-place concrete piersconsisting of arched concrete unitssupporting pilasters provide contrast andenhance the concrete arched girders. Insection, each pier and abutment flaresto match the arch of the supportedgirder. <strong>The</strong> piers are rounded at eachend supporting a total of 10 decorativepilasters. <strong>The</strong> pilasters were precast andinstalled on supports on the piers. Bydoing so, the contractor was able toeliminate intricate forming at each pierand accelerate the construction schedule.<strong>The</strong> pilasters surrounding the main spanswere 19 ft tall, 9 ft wide, and 4.5 ftdeep.Balustrade Railingsand MedallionsMore than <strong>11</strong>00 individual precastconcrete pieces were required for therailings. Four custom logo medallionswere produced and attached at thecrowns of the arches.Utilities and Traffic IssuesUtilities were a problem and caused morethan minor delays. Haven Avenue is autility corridor that includes buried wetand dry utilities, in addition to overheadpower and communication lines.During project construction, utility linerelocation caused a 5-month delay inthe construction schedule. Aggressiverescheduling was required to keep thebridge and roadway project on track.Throughout construction of the bridge,rail traffic continued on schedule withoutdisruption. Two lanes of vehicle traffic ineach direction remained open on HavenAvenue during peak travel times, usinga temporary bypass parallel and adjacentto the west side of Haven Avenue. <strong>The</strong>avenue was closed to traffic on onlytwo limited occasions when an alternatetraffic detour was constructed and laterremoved.Low Price,Inestimable Value<strong>The</strong> Haven Avenue underpass bridgewas completed in only 13 months—ahead of schedule—between November2008 and December 2009. Accordingto the Southern California Regional RailAuthority, this was the fastest gradeseparation construction of this scale tobe completed in the region. Even better,the architecturally significant projectcost $2 million less than the engineer’sestimate of $16 million (excluding rightof-wayand engineering costs).<strong>The</strong> innovative bridge has remediedmultiple problems. <strong>The</strong> traffic bottleneckat grade has been removed, resulting insmoother flowing traffic and improvedmotorist safety. Fuel emissions fromidling vehicles has been greatly reduced,which contributes to better air qualityand a healthier environment. New20 | <strong>ASPIRE</strong>, <strong>Spring</strong> 20<strong>11</strong>
sidewalks have increased mobility forpedestrians and bicyclists.<strong>The</strong> bridge’s ornamental railing, boldcolor, massive columns, and curvilinearform has given Rancho Cucamongaan impressive city landmark thatcompliments the dramatic backdropprovided by the mountain range. Havingan architecturally significant entrymonument to Rancho Cucamonga ishelping to improve the livability of thecommunity, attract new businesses, andenhance property values—all of whichcontribute to improving the lives of localresidents.__________Miguel A. Carbuccia and Sam S. Xie aretransportation project managers with PBS&J,an Atkins company, in Orange, Calif.For additional photographs orinformation on this or other projects,visit www.aspirebridge.org and openCurrent Issue.<strong>ASPIRE</strong>, <strong>Spring</strong> 20<strong>11</strong> | 21
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