Kapalua
Bridge, 2008
Kapalua
Adventure Course, Maui
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Satellite View of Project Location View Larger Map
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Kapalua
Bridge, 2008 Kapalua
Adventure Course, Maui
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Satellite View of Project Location View Larger Map |
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USE: Pedestrian SPAN: 360' TRAVEL WIDTH : 5' TOWERS: 52' tall, A 588 Weathering Steel Lattice Column ANCHORS: 6' x 6' Earth anchor @ 18 ft soil burial depth each mainline pair MAINLINES: Twin Pairs 1-1/4" Galvanized Structural Strand |
| Kapalua Bridge, 2008 |
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The Kapalua Bridge soars over Kaopala Gulch in the West Maui Mountains, 1600 feet in elevation above the northwest Maui coastline. It is the most recent addition to Kapalua Resort's renowned mountain adventure course, a world-class facility that includes many thousands of feet of ziplines, climbing walls, and a ropes course. At a span of 360 feet, the Kapalua Suspension Bridge is the longest suspension bridge in Hawaii, and its 200 foot height makes it the highest pedestrian-only bridge (of any kind) in the US. During the wet winter season one can look 120 feet down to where Kaopala Stream waters accumulate before vaulting off a rocky precipice and cascading 80 feet into the depths of the gulch. The sweeping view from the bridge deck of Molokai and Lanai Islands and the limitless expanse of ocean stretching to the horizon is breathtaking, especially at sunset. Spectacular rainbows above, below, or surrounding the bridge are an almost daily event. Nearby, zipline travellers of every age and description soar through space, providing ample live entertainment. An expansive biological preserve sits uphill of the bridge site and boasts one of the most biodiverse regions in the islands.
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View of Maui uplands and lattice column tower. |
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Shipment of the bridge from Seattle to Maui required three 40-foot shipping containers, containing well over 100,000 pounds of pre-fabricated bridge components and all of the requisite tools. Once on Maui, Sahale staged material through the Maui Gold pineapple fields and to the bridge site on the mountain high above with two flatbed trucks, a grade-all fork lift and two pickups. During peak production Sahale had a crew of nine excavating, building abutments, and assembling tower legs. Construction took seven weeks, start to finish. The famous (and persistent) Pacific Trade Winds of 20-30 mph blew constantly, making rope work, rigging, and certain installation steps an interesting challenge. Anticipating even higher winds over the life of the structure, the Kapalua Bridge was designed with heavier components and internal sway bracing so that it can withstand hurricane force winds exceeding 105 mph. This is the first Sahale bridge to incorporate lattice column towers, and to have a three pipe (handrail, grab rail and kick rail, see left) hand rail arrangement integrated with the cable railing system. The double mainline pairs are unusual but an effective, redundant design first used in a Sahale suspension bridge in 1995 (Tawkes-Foster). Lattice column towers are a throwback to steel fabrication practice in the late 19th and early 20th Century and were chosen by the Owner to evoke timeless appeal. There are many parts in a lattice column: The Kapalua Bridge towers are comprised of 1656 lace bars and 3600 fasteners. The concrete abutments are anchored with helical piles driven 45 to 65 feet deep into the bedrock, and the concrete-filled steel earth anchors are buried 18 feet deep. The towers and superstructure are A588 weathering steel and the decking is composed of lightweight slip-proof UVA-rated pultruded fiberglass grating. The mainlines, suspender cables and under-deck diagonal cables are all galvanized structural strand or wire rope of Independent Wire Rope Core (IWRC) design.
(Additional images of construction of the Kapalua Suspension Bridge are collected at Bridgemeister.) |
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| View of railing, suspenders, superstructure, and double mainline pairs. | ||
