新型复合板与钢筋混凝土码头的可靠性分析-毕业论文外文翻译.docx

9th Int'l Conference on STELL ,SPACE &COMPOSITE :10-15 OCT 2007,Yantai&Beijing,China RELIABILITY ANALYSIS OF NEW TYPE COMPOSITE PANELS OF STELL AND CONCRETE FOR WHARFSChang hong Huang*，Navy University of Engineering , tianjin，ChinaZhuo bin Wei . NaVy University of Engineering，tianjin,chinaABSTRACTNew type steel-concrete composite slabs with stiffening ribs were porposed aspanels of wharfs to meet special requirements. Working procedure of a wharf can bereduced and project construction speed can be fester by using this new type steel-concrete composite slabs . Based on the statistic parameters of load and materialcharacters and dimensions，the security and reliability for the new type steel-concrete slabs for wharfs in the periods of construction and using in sea arecalculated and compared with common concrete panels of wharfs . By the calculatedresults，advices of the new type steel-concrete structure for wharf on Piles areproposed.KEY WORDS: new type steel-concrete composite slabs with stiffening ribs , wharf，concrete structure，reliability，and construction period1. Introduction Stell-concrete composite structure has been applied widely in the buildingproject，but it is seldom applied in wharfs in sea . Instead of reinforced concrete beam-slab system，a new type steel-concrete composite structure is designed for wharf on piles to meet special requirements. A type of composite beam with concrete and U-shaped steel is designed as the beam of wharf on piles，and a new type of steel-concrete composite slab with stiffening ribs is designed as the panel of wharf on piles.Steel slab with stiffening ribs can span a long distance without any temporary braces; furthermore，it has bigger carrying capacity than RC slab has during construction，and after integrating with concrete the steel-concrete composite slab with stiffening ribs can support more loads .Because the construction of this slab needn't use moulding board and bind reinforcing steel bars . working procedure of a wharf can be reduced and project construction speed can be faster by using this new type steel-concrete composite structure . And because this Steel-concrete composite slab has less deadweight,the hoist ability off floating crane will not be so important in building a wharf U-shaped steel concrete composite beam has the same advantage . Thus this steel-concretecomposite structure system is a good choice to build a wharf on Piles under brief time limit for a project.The new type of stell-concrete composite structre is researched to apply in wharfs ,so there are few experiences of design，construction and use of the application of the composite structure in wharfs .Based on the statistic Parameters of load and material characters and dimensions，the security and reliability for the new type steel-concrete slabs for wharfs in the periods of construction and using in sea are calculated and compared with common concrete panels of wharfs . Based on the calculated results advices of the new type steel-concrete structure for wharf on piles are proposed.2. The new type of composite beam-slabs systems2.1 Beam-slabs systemsTo meet the requirements of a wharf on piles in sea,two kinds of composite structure are adopted to form a new type of composite structure beam-slabs system(Fig.1). One is U-shaped steel concrete composite beam which is also called cap-style section composite beam，The other is the ribbed steel form concrete composite slabs or the steel sheeting-concrete composite slabs with the reinforced bar of profiled steel. Welding or cold bendings slabs into the U-shaped section as the beam's rib,pouring concrete into the rib and the upside of flange on the U-shaPed section,the U-shaped steel-concrete composite beam is formed.According as require，U-shaped steel beams can adopt the type of the section with liPPed bar or the section without lip，just as Fig.2. When the U-shaped steel has the lipped bar，one way is to lay the bottom slabs on the lipped bar and root them with bolt( as Fig.2(a).The other way is to groove firstly on the bottom slabs and connect it with the lipped bar by plug welding. when the U-shaped steel beam has not the lipped bar，the end of slabs may be extended in to concrete of the beam，then they are braced on the side rib of U-shaped steel beam(as Fig.2(b)，and the width of this kind of U - shaped steel beam is longer.2.2 Steel-concrete composite slabs with stiffening ribs slab0n the bottom of the steel-concrete composite slabs with stiffening ribs slab，is welded into the steel deck on which the certain concrete is poured(Fig.3).The slab is one-way slab , and the I-shaped steel or the T-shaped steel must be Paralleled to the direction of the span of the slab . If the slab is designed as one-way continuous plate，reinforcing steel bars can be set at the upside of the slab on the bearing by calculation . Because of stiffening ribs，the slab can endure big shearing force and needn't set reinforcing steel bars to resist it .To make the steel and concrete of the slab work as a whole , bolts are welded into the bottom of the steel deck and the top of the I-shaped steel or the T-shaped steel.3 . Reliability analysis of the steel-concrete composite slab with stiffening ribs in wharf on pilesThe structural reliability is the Probability of a structuer realizing its Pre-design function in certain Period and certain conditions . In this paper , the reliability for the steel-concrete composite slab with stiffening ribs in wharf on piles is analyzed . Based on the limit state of bearing capacity,JC method is applied into the calculation of the slab's reliability index 56. 3.1 Calculating model of resistanceThere are three factors that influence the randomicity of the resistance of structure members mainly . These factors are material property ，geometrical parameter of the members and calculating mode. For the steel-concrete composite structures，the randomicity of geometrical parameter of the members can be determined by each statistical parameter of steel members and concrete members . Then the randomicity of material ProPerty，which mainly refers to the strength of the material，can be obtained after analyzed the statistical data of each kind of materials of the slab . For the randomicity of calculating mode，because of the lack of its statistical date ,it is not be discussed in this PaPer，and choosing a Proper calculating model of resistance is a appropriate way to reduce its influence.During construction，only the resistance of the steel components in the steel-concrete composite slab with stiffening is accounted, and the concrete of the slab is merely regarded as load . So the flexure strength of the slab can be calculated by ordinary steel structure calculating method，and we do not discuss more about it . During service life，steel components and concrete can work as a whole , and the natural axis of the composite slab should be designed to pass the webs of profiled steel2. Then the height of compressive region can be figured out by the balance of force.Where fa is design value of compressive and tensile strength of steel slab; fs is design value of compressive and tensile strength of profiled steel; fc is design value of compressive strength of concrete;Aa is area of steel slab; Af is area of tensile flange wall of profiled steel; b is width of composite slab;Asf is area of compressive flange wall of profiled steel;tw is web depth of profiled steel;hs is web height of profiled steel(viz. the approximatively total height of profiled steel) ;hc is distance between the compression flange wall of profiled steel and the top of concrete;b is width of composite slab;nis amount of profiled steel on slab width.The value of x figured out by the formula (3) must be given as follows: X<hc+hf.otherwise the slab should be redesigned . Where hf is flange depth of profiled steel . Then the flexure strength is given byShear strength of the obligue section of the steel-concrete composite slab with stiffening ribs can be figured out by formula(3). Where Vc is design value of shearing strength of concrete;Vs is design value of shearing Strength of profiled steel.If the composite slab is designed as one-way continuous plate and reinforced steel bars are assigned in the upside to resist negative moment ,the bearing capacity of negative moment resistance formula of U-shaped steel-concrete composite beam3.3.2 Model of loadActions that may affect a wharf on piles can be classified as permanent action and variable action and accidental action，and the effect of accidental action isnt involved in this paper.The main permanent action of a wharf on piles is the action of the dead loads of the component of the wharf. The dead load distribution of wharf on piles is normal distribution，and the statistic parameters are given as follows . The mean value is given by ; the variance is given ;the variable coefficient is given by . Where is design value of dead load. The actions of the loads of the heaped load and carnes and trucks are the variable actions that a wharf on piles may suffer，and the heaped load often has the main effect . The heaped load distribution conforms to the Extreme I distribution . The statistic parameters are given by the appendix of the Code JTJ215一98.3.3 Calculation of reliability indexIn this PaPer，JC method is applied in the calculation of the composite slabs reliability index The limit state equation is given as folLows，Where Zis the limit state function;Ris the resistance of the structure;is the effect of Permanent actions; Is the effect of variable actions.Because the slabs in the upside of wharf on Piles are usually continuous plates，what's the brief failure mode must be taken into account to figure out the reliability index of the composite slabs . The new tyPe steel-concrete comPosite slabs with stiffening ribs are designed to rePlace old concrete slabs with equal or aPProximate bearing capacity of flexure strength，and the shear strength resistance caPacity of the composite slabs is usually bigger than the old one's . Therefore，considering the correlation of three failure modes，the reliability index of the middle section is regarded as the representative reliability index of the whole slab with enough precision.3.4 Calculation of an instance3.4.1 Introduction of the structureWithout longerons ，Prefabricated RC slabs were Put on the crossbeams directly in the wharf on Piles，and the distance between two crossbeam is 6.0m .As one-way continuous Panels,the slabs are hinged in transverse . The length of the slabs is 5600 mm，and the width is 2700 mm，and the thickness is 500 mm. The concrete degree of the slabs is C40 . 21 reinforced bars with 18 mm diameter were assigned in the downside of each RC slab. As design variable load，the heaped load were given,and its representative value is 20KN/m2 . In the construction period ,the representative value of construction load is 2.5KN/m2.New tyPe steel-concrete composite slabs with stiffening ribs are designed to rePlace the old RC slabs with the aPProximate bearing capacity of flexure strength . The length of the composite slabs is 560O mm , and the width is 270O mm，and the thickness is 250 mm .The concrete degree of the slabs is C40 . Each composite slab has 6 stiffening ribs ，which are made by ll4 shaped steel，and the bottom steel Plate is 5 mm in thickness . All the steel components are made from Q235 steel . TO resist shear strength and make the composite slab work as a whole , bolts are welded on the top of the I-shaped steel and the bottom steel Plates . In this PaPer，the old RC slab is noted as SLABO，and the new tyPe composite slab is noted as SLAB1.3.4.2 Result of the reliability calculationBased on JC method , reliability indexes of the old slab and the new type composite slab are calculated，and the result is listed as the Table 1.The durability for the wharf on Piles in sea is also imPortant , and it is discussed in this PaPer.Time-dependent reliability indexes for the RC slabs of the wharf with changing characters are calculated with the corrosion rate of 8.0 m/ , and the calculated results are showen in Fig.4.4. ConclusionsA new type steel-concrete composite structure is porposed to replace the upside structure of wharf on piles for some special purposes . The reliability for the steel-concrete composite slab with stiffening ribs is discussed , and an instance is calculated . By analyzing the result ，some conclusions can be down as follows.With approximate bearing capacity of flexure strength , the reliability for the new type steel-concrete composite slab with stiffening ribs is bigger than the old RC slab's . Therefore , being safe enough ，the new type composite slabs are advised to replace RC longerons and RC slabs of wharfs on piles for their emergency repair or construction.Because of the high resistance capacity of the stiffening I-shaped steel ribs , the reliability index of the new type composite slabs during costruction period is higher than that during service period . So the new type composite slabs can carry more construction load in safe , and it can speed the building Work in a way.Because of the corrosion of the steel bottom slabs , time-dependent reliability for the new type composite slabs keeps falling smoothly , and the falling speed is quicker than that of the RC slabs during the first 15 years . After 15 years ，with the corrosion of the inside reinforced steel bars , the time-dependent reliability for the RC slabs drops quickly . Therefore ，to have enough durability ，some available measures must be taken to protect the exposed surfaces of the composite slabs' steel components . And in long term ，the durability for the composite slabs is better than the RC slabs .Reference1 WEI Zhuo-bin，WANG Tie-cheng & ZHANG Xiao-Peng . New Type Composite Panels of Steel and Concrete for QuaysJ- China Harbour Engineering ,2006(3):24-282 WEI Zhuo bin，Gao Yi & Wang Tiecheng. Test of A New Type of steel-concrete Composite Slab With shape Stiffening RibJ . Steel Construction，2006，27(1):77-823 PLA General Logistics Department . Technical Specifications for Early-strength Model Composite Structure Used for Navy Port Emergency RePair in Wartime(GJB4142-2000) . Beijing : PLA General Logistics Department ，2000-12-264WEI Zhuo bin，GAO Yi & XUE Songtao . Construction and strength calculation of a new type of composite structure beam-slabs system A ，The Ninth International Symposium on Structural Engineering for Young ExPertsC ，Fuzhou & Xiamen ，China : Han Linhai , 2006:1445-14505HUANG Changhong . Reseach on Evaluation of The Durability of Existing Open Type Wharf on Piles : M.S.Dissertation . Tianjin :Tianjin University , 20046WANG Yuan-zhan ，SUN Yi & HUANG Changhong . On Ti