一、概述1977年5月在宫崎县北部一个狭窄溪谷上建成了一座上承式预应力混凝土吊桥一速日峰桥(见图1、图2)。(一)现场状况建桥地点沟深约50米,两岸是56°～60°倾斜直立的陡峭悬崖。这一地带的基岩为中生代至古第三纪的千页岩。地表面约1米左右为风化岩或表土覆盖,以下为坚固岩层。因地形所限,施工现场很狭窄,限制了重型 I. Overview In May 1977, a roof-supported prestressed concrete suspension bridge-speeding day bridge was built in a narrow valley in the north of Miyazaki County (see Figure 1 and Figure 2). (A) site conditions Bridge site ditch depth of about 50 meters, the two sides are 56 ° ~ 60 ° tilt upright steep cliffs. The bedrock of this area is a thousand shale from Mesozoic to Paleogene. About 1 m above the surface of the weathered rock or topsoil coverage, the following is a solid rock. Due to the limited terrain, the construction site is very narrow, limiting the heavy type