超寬箱梁多桁片組合掛籃施工技術(shù)研究

摘 要：該施工技術(shù)采用前上橫梁、后上橫梁將4片三角式主桁架主縱梁連接成整體形成多桁片組合掛籃。組合式掛籃的多片縱梁能有效地分配懸澆混凝土荷載，能避免由于梁段過重導(dǎo)致的主縱梁局部失穩(wěn)現(xiàn)象，降低已澆節(jié)段混凝土的拉壓應(yīng)力（錨點(diǎn)抗拉反力和中支點(diǎn)承壓力）。且梁段澆筑時(shí)，底模平臺(tái)的底縱梁共同受力，協(xié)調(diào)變形，能有效防止掛籃前面發(fā)生扭轉(zhuǎn)失穩(wěn)，提高整體橫向穩(wěn)定性。多桁片組合掛籃總重約177 t，占最大節(jié)段重量的39.3%，具有自重輕，剛度大、變形小，結(jié)構(gòu)簡(jiǎn)單，受力明確等特點(diǎn)，能有效解決超寬截面梁段在掛籃懸臂施工時(shí)的應(yīng)力分布和撓度變形問題。由于使用通用設(shè)備，具有較好的參考意義。

關(guān)鍵詞：超寬箱梁；多桁片；組合掛籃；應(yīng)力分布；撓度變形

中圖分類號(hào)：U445.4 文獻(xiàn)標(biāo)志碼：A 文章編號(hào)：2095-2945（2024）29-0173-05

Abstract： In this construction technology， the front upper beam and the rear upper beam are used to connect four triangular main truss longitudinal beams to form a multi-truss composite hanging basket. The multiple longitudinal beams of the combined hanging basket can effectively distribute the suspended concrete load， avoid the local instability of the main longitudinal beam caused by the overweight of the beam section， and reduce the tensile and compressive stress of the cast segment concrete （anchor tensile reaction force and middle fulcrum bearing pressure）. When the beam section is cast， the bottom longitudinal beam of the bottom formwork platform is subjected to common force and coordinated deformation， which can effectively prevent torsional instability in front of the hanging basket and improve the overall lateral stability. The total weight of the multi-truss combined hanging basket is about 177 t， accounting for 39.3% of the maximum segment weight， which has the characteristics of light weight， large stiffness， small deformation， simple structure， clear force and so on. It can effectively solve the problem of stress distribution and deflection deformation of ultra-wide cross-section beam during the cantilever construction of hanging basket. Due to the use of general equipment， it has a good reference significance.

Keywords： ultra-wide box girder; multi-truss plate; combined hanging basket; stress distribution; deflection deformation

懸澆施工采用的掛籃，根據(jù)錨固方式的不同可分為后支點(diǎn)掛籃、前支點(diǎn)掛籃，根據(jù)構(gòu)造形式和受力體系不同可分為桁架式掛籃、斜拉式掛籃、牽索式掛籃及復(fù)合式掛籃。其中，桁架式掛籃受力主桁架的結(jié)構(gòu)形式不同，常見的有平行桁架式掛籃、弓弦式掛籃、三角式掛籃和菱形掛籃等。對(duì)于超寬（寬度超過30 m）箱梁懸臂施工，若采用雙榀主桁架三角斜拉式掛籃對(duì)節(jié)段進(jìn)行整體一次性澆筑，掛籃主梁應(yīng)具有很大的剛度，同時(shí)掛籃的自重大幅度增加，造成材料上的浪費(fèi)，且由于掛籃的自重增加過大，會(huì)產(chǎn)生很大的錨點(diǎn)反力和壓應(yīng)力，通常會(huì)超過設(shè)計(jì)和規(guī)范要求的上限，影響結(jié)構(gòu)的安全。……