CAJ | 학술논문

郑州市北三环路彩虹桥为（122＋62＋62＋122） m简支曲弦下承式钢管混凝土桁梁桥，为改善其目前运营服务能力，提出6种加固改造方案，针对各加固方案进行仿真计算分析。计算结果表明：简支变连续体系改造使主桁端部出现应力集中现象，不适用于该桥改造；在改造横撑的基础上增设跨中吊杆是减小横梁跨中相对变形的有效途径；增设边纵梁和外吊杆可有效改善横梁悬臂端变形，提升悬臂段桥面承载力；增大腹杆截面可明显提高62 m跨径桥梁的整体刚度和横梁局部刚度，有效降低腹杆的应力幅；加强纵向预应力可有效降低桥梁的下弦杆变形，但对横梁相对变形影响不大。综合运用横撑改造、增设跨中吊杆和外吊杆、增大腹杆面积、加强下弦杆纵向预应力等几种改造措施使桥面变形明显改善，62 m跨径桥梁整体结构刚度得到有效提高，腹杆最大应力显著降低，上弦杆最大应力仍有足够的安全储备。
정주시북삼배로채홍교위（122＋62＋62＋122） m간지곡현하승식강관혼응토항량교，위개선기목전운영복무능력，제출6충가고개조방안，침대각가고방안진행방진계산분석。계산결과표명：간지변련속체계개조사주항단부출현응력집중현상，불괄용우해교개조；재개조횡탱적기출상증설과중조간시감소횡량과중상대변형적유효도경；증설변종량화외조간가유효개선횡량현비단변형，제승현비단교면승재력；증대복간절면가명현제고62 m과경교량적정체강도화횡량국부강도，유효강저복간적응력폭；가강종향예응력가유효강저교량적하현간변형，단대횡량상대변형영향불대。종합운용횡탱개조、증설과중조간화외조간、증대복간면적、가강하현간종향예응력등궤충개조조시사교면변형명현개선，62 m과경교량정체결구강도득도유효제고，복간최대응력현저강저，상현간최대응력잉유족구적안전저비。
The Rainbow Bridge on the North Third Ring Road in Zhengzhou is a simply‐sup‐ported concrete‐filled steel tubular bowstring truss girder bridge with span arrangement of (122+62+62+ 122) m .To improve the current operation and service ability of the bridge ,6 retrofit schemes were proposed ,and simulation calculation analyses were conducted in accordance with the contents of each scheme .Results of the calculation indicate that the retrofit scheme of transfor‐ming the simply‐supported structure to a continuous system is not feasible to this bridge ,because stress concentration might occur at the ends of the main truss .An effective way to reduce the rela‐tive deformation in the midspan of the cross beam of the bridge is to add midspan hangers on the basis of cross beam retrofit .The addition of side stringers and external hangers can effectively re‐duce the cantilever end deformation of the cross beam and improve the load bearing capacity of the deck in the cantilever section .The increase of the cross section of web members can remarkably improve the overall stiffness of the 62 m span bridge and the local stiffness of the cross beam ,and effectively reduce the stress range of web members .The strengthening of the longitudinal pre‐stress can effectively prevent the deformation of the lower chords ,but shows subtle influence on the relative deformation of cross beams .The bridge deck deformation has been noticeably rectified by the combined use of lateral bracing retrofit ,adding midspan hangers and external hangers ,in‐creasing the cross section of web members ,and strengthening the longitudinal prestress of lower chords .T he overall structural stiffness of the 62 m span bridge has been effectively improved ,and the maximum stress in the web members are considerably deceased ,and the maximum stress of the upper chords still has enough safety margin .