本文作者:linbin123456

頭部信托-南水北調1號水庫項目非標政信

linbin123456 2023-12-01 34
頭部信托-南水北調1號水庫項目非標政信摘要: 【頭部信托-南水北調1號水庫項目非標政信】????國家重大戰略設施項目????省會AA+主體融資????傳統非標政信【規?!?.8億100-300-1000萬:12月 6.4%-6....
【頭部信托-南水北調1號水庫項目非標政信】????國家重大戰略設施項目????省會AA+主體融資????傳統非標政信
【規?!?.8億
100-300-1000萬:12月 6.4%-6.8%-7.1%(稅后)
【風控措施】西安灃東發展集團有限公司為灃東控股的股權收購義
務提供不可撤銷連帶責任保證擔保。
【資金用途】本信托用款項目斗門水庫項目——為國家和陜西省重點水利工程,斗門水庫項目為國家南水北調工程水庫項目,已被列入全國水利改革發展“十三五”規劃和陜西省2023年重點項目名錄
【項目亮點】
??AA+主體融資方:西安灃東控股有限公司是灃東新城管理委員會100%持股的一級平臺公司,是灃東新城內實力最強,最核心的平臺公司。公司目前最新主體信用評級為AA+評級展望為穩定。
??擔保人:西安灃東發展集團有限公司,公司成立于 2009年,注冊資本 100 億元,其承擔灃東新城規劃范圍內區域發展投融資、城市基礎設施建設及園區配套開發與運營等工作。2021 年末,灃東集團資產總額為636.12億元,2021年公司實現營業收入 43.10 億元,凈利潤 1.66億元。公司具有較強的再融資能力,主體信用評級為 AA,外部認可度較高,融資渠道暢通,具有擔保能力。

信托定融政信知識:

對設計實際工程中異形柱結構的分析計算、構造措施等方面進行了探討,并給出成功的工程設計實例

     Abstract: this paper expounds on the loading characteristics of special-shaped column frame, the design of special-shaped column structure in practical engineering analysis and calculation, construction measures and so on are discussed in this paper, and successful engineering design example is given.   關鍵詞:異形柱;框架 Key words: special-shaped columns; The framework      1 前言 1 introduction      近年來,異形柱框架或異形柱框架一剪力墻結構作為一種全新的結構形式廣泛用于小高層住宅建筑中,相對于傳統的短肢剪力墻或框架結構,能更好的滿足建筑需求且造價略有降低,因此具有更好的經濟效益和社會效益

    該結構形式一般指同層內異形柱數量超過柱總數量10%的框架或框架剪力墻結構,適用抗震設防烈度為6度或7度的地區

     In recent years, special-shaped column frame or special-shaped columns frame shear wall structure as a new kind of structure widely used in small high-rise residential buildings, compared with the traditional short limb shear wall and frame structure, can better meet the construction demand and cost is slightly reduced, therefore has better economic and social benefits. Within the structure generally refers to namely special-shaped column more than 10% of the total number or frame shear wall structure, the framework of applicable seismic fortification intensity is 6 or 7 degrees.      2 受力特點 2 mechanical characteristics      異形柱是指柱截面擯棄了慣用的矩形柱,而采用多個小墻肢的組合截面柱子,由剪力墻演變而來

    柱肢截面中各肢高厚比不大于4,常用的有L形、T形和十形,亦有采用Z形

    柱肢寬度一般使用與墻體相同的厚度,一般為200~250mm,不大于300mm

    肢長較大,《規程》規定不小于500mm,一般為600~800

    除此之外,不等肢異形柱肢高比一般不超過1.6,各肢截面厚度不能相差過大

     Special-shaped columns is refers to the column section away from the conventional rectangular column, and use multiple small wall limb combination section columns, the shear wall. Column leg section high thickness ratio is not greater than 4 in each limb, commonly used is l-shaped, t-shaped and ten shape, also have use Z. Column limb width generally use the same as the wall thickness, average for 200 ~ 250 mm, no greater than 300 mm. Limb length is larger, "rules" regulation is not less than 500 mm, generally is 600 ~ 600. Besides, ranging from limb special-shaped column limb ratio is generally not more than 1.6, the leg section thickness can not differ too much.   雖然異形柱由剪力墻演變而來,但由于柱截面本身的特殊性,異形柱結構的受力特點既不同于剪力墻結構,也與普通框架相差很大,具有自己的獨特性,在荷載作用的結構反應更加復雜

    國內外大量的試驗資料和理論分析證明,異形柱的破壞形態有:彎曲破壞、小偏壓破壞、剪壓破壞等,影響破壞形態的因素主要有:荷載角、軸壓比、剪跨比、配箍率等

     Although special-shaped columns composed of shear wall has evolved, but due to the particularity of the column section itself, the load-bearing characteristics of the special-shaped columns is different in shear wall structure, and general framework also vary widely, has its own uniqueness, the load of the structure response is much more complicated. At home and abroad a large number of experimental data and theoretical analysis prove that the damage form of special-shaped columns are: bending failure, small bias damage and shear damage, etc., are the major factors influence the failure pattern, loading Angle, axial compression ratio, shear span ratio, stirrup ratio and so on.   2.1整體計算分析 2.1 overall calculation and analysis   異形柱的存在和不同的布置對結構整個抗側力剛度影響很大,總體來講相對于同樣布置的同截面矩形柱結構,異形柱結構的整體性要好,剛度略由增強;而單結構形式來講,異形柱結構的剛度介于普通框架和框架剪力墻之間

    文獻【2】對8度區-6層住宅分別采用矩形柱和異形柱框架進行設計,然后分別采用SATWE和CRSC程序對比分析,結果表明在地震作用下異形柱結構的底部剪力要比矩形柱框架結構大16%~26%左右,各層柱的平均剪力和節點剪力也比矩形柱框架大很多

    異形柱結構的受力特點介于普通框架柱和剪力墻之間,結構的抗震性能比較差,在內力分析計算時,既不能完全按普通框架柱,也不能完全照搬短肢剪力墻

     The existence of the special-shaped columns and different arrangement of great influence on the whole stiffness to resist lateral force structure, in general compared to the same arrangement with the cross section of the rectangular column structure, special-shaped column structure integrity is better, slightly by enhancing stiffness; And single structure, special-shaped column structure stiffness between ordinary frame and shear wall frame. Literature 【2】, respectively for 8 degrees area - 6 layer housing design and special-shaped column frame with rectangular column, and then respectively by using SATWE and CRSC program comparison and analysis, results show that the structure with special-shaped columns under seismic action at the bottom of the shear force is about 16% ~ 26% larger than the rectangular column frame structure, the average shear shear and node of each column is a lot larger than the rectangular column frame. Special-shaped column structure of mechanical characteristics between ordinary frame column and shear wall, the structure's seismic performance is poor, the internal force analysis and calculation, neither completely according to the common frame column, also can not completely copy the short limb shear wall.   根據規范要求,對于矩形柱結構,當無斜向抗側力構件時,結構設計的地震作用方向一般取工程縱橫軸方向,即0°和90°以此來求得地震作用下的結構內力,正截面承載力兩個方向分別按單偏壓計算配筋,其承載力基本上可以包絡地震作用沿其他方向的情況

    但對于異形柱,由于截面慣性矩沿不同方向差別很大,地震作用下柱受力的最不利方向不一定0°或90°,也就是說僅沿該兩個方向計算的正截面配筋并不能完全包絡地震作用沿其他方向時的情況,尤其在高烈度地區體現得更顯著

    對此,《規程》強制規定,7度及以上時地震作用尚應對與主軸成45°方向進行補充驗算

     According to specification requirement, the rectangular column structure, when no oblique component to resist lateral force, structure design of the seismic action direction generally take engineering vertical and horizontal axis direction, namely 0 ° and 90 ° to obtain structural internal force under earthquake action, normal section bearing capacity of two directions respectively by single bias of reinforcement calculation, its bearing capacity can be basically envelope along other direction seismic action. But for special-shaped columns, as a result of section moment of inertia along different direction difference is very big, the earthquake under the action column stress does not necessarily the most unfavorable direction 0 ° or 90 °, that is to say, only along the direction of the two calculating the normal section of reinforced not completely enveloping along the other direction seismic action, especially in high intensity areas is more prominent. To this, "discipline" mandatory regulation, 7 degrees and above the seismic action is still coping with the spindle on supplement 45 ° direction.   考慮到受力后異形柱結構反應復雜,抗震性能不好,為符合“三水準兩階段”的抗震設計思路,地震作用計算后梁柱的內力調整都相對要求更嚴格些

    對此,目前國內通用的結構設計軟件PKPM并沒有體現出來,雖然可以建立異形柱的模型,但尚未增加異形柱這種結構形式

    其內部的內力調整和截面配筋計算仍然按照矩形柱或者短肢剪力墻的模式進行的,這難免會帶來誤差,有時可能相差甚遠

    天津大學開發的異形柱設計軟件CRSC尚未普及

     Considering the complicated mechanical structure with special-shaped columns after response, seismic performance is not good, to meet the "three levels and two stage" seismic design train of thought, after the earthquake action calculation beam internal force adjustment are relative requirements more strict. To this, the current domestic general structure design software PKPM is not reflected, while it is possible to establish models of special-shaped columns, but not yet increase form the structure with special-shaped columns. Its internal internal force adjustment and calculation of steel is still in accordance with the rectangular column or short limb shear wall model, this will inevitably bring error, sometimes may be far. Special-shaped columns design software developed by tianjin university CRSC hasn't been widespread.   目前很多設計都是把異形柱作為短肢剪力墻,按短肢剪力墻結構利用PKPM等空間軟件進行分析設計,誤差大在所難免

    相對精確的設計方法是:假設梁柱節點與普通框架梁柱節點相同,按等主軸剛度及等截面面積兩個條件把異形柱截面轉化成等效矩形柱截面,利用空間有限元分析程序進行內力分析,求出柱的內力重新按照有關異形柱截面的配筋計算公式進行截面配筋驗算

    但這種等效轉化后的計算模型仍與實際結構有較大出入,由于異形柱肢長比較大,與梁相交時梁柱重疊部分較大,形成類似與壁式框架的梁柱剛域,梁的計算長度大大減小,實際結構的側向剛度比計算模型大,導致地震力計算偏于不安全,文獻【3】對柱內力在程序計算結果的基礎上乘以約1.1的放大系數或者加大周期折減度以適當考慮其影響

    但這也是權宜之計,且對于普通設計人員來講過于費時費力,不利于提高效率

     At present a lot of design are the special-shaped column as a short limb shear wall, according to the space such as short limb shear wall structure by PKPM software carries on the analysis and design, error is inevitable. Relatively precise design method is: assume beam-column node is the same as the ordinary beam-column node, according to the spindle stiffness and the cross section area of the two conditions, such as special-shaped columns section is converted into equivalent rectangular column section, the use of space finite element analysis program for internal force analysis, the internal force of column again in accordance with the relevant calculation formula of special-shaped column section reinforcement section reinforcement calculation. But this kind of the calculation model of equivalent transformation after still have larger in and out, and the actual structure with special-shaped columns limb is larger, and larger beams intersect and overlap, form similar to Liang Zhugang domain wall frame, the calculation of beam length greatly decreases, and the actual structure of the calculation model for the lateral stiffness ratio is big, cause the earthquake force calculation be unsafe, the literature 【3】 on the internal forces of the column on the basis of calculation results are superior to about 1.1 degree of amplification coefficient or increasing cycle time reduction with due consideration of its impact. But this is temporary solution, and for ordinary designers are too time-consuming, not conducive to improve efficiency.      2.2正截面受彎承載力和斜截面受剪承載力 2.2 flexural bearing capacity of normal section and inclined section shear bearing capacity   柱肢截面的差異,導致柱肢平面內外兩個方向的截面特性相差較大,異形柱截面在軸壓力及彎矩剪力共同作用下,正截面承載力的計算是一個十分復雜的問題,因為柱截面中和軸一般不與彎矩作用平面相垂直,也不與截面邊緣平行,其位置隨截面尺寸、混凝土強度、配筋率及荷載角等諸多因素的變化而變化

    進而導致柱肢平面內外兩個方向的慣性矩差異明顯,進而側向剛度相差較大,對不等肢的截面表現尤甚

    因此普通柱正截面抗彎驗算的計算公式并不適用于異形柱,《規程》將異形柱截面劃分為有限個混凝土單元和鋼筋單元,仍然采用平截面假定給出了雙向偏壓的正截面承載力驗算公式

     Column leg section differences, cause inside and outside column limb planar section features large difference in two directions, special-shaped cross-section under axial stress and bending shear joint action, normal section bearing capacity calculation is a very complicated problem, because the column section neutral axis is generally not plane, vertical and bending moments is not with the cross section parallel to the edge, its position with the cross section size, concrete strength, reinforcement ratio and load Angle changes, and many other factors. Leading to column limb planar inside and outside two direction inertia difference is obvious, and the lateral stiffness is large, the range of limb section performance. So ordinary column calculation formula of normal section bending calculation does not apply to special-shaped columns, the regulation will be special-shaped column section is divided into a finite number of concrete and steel units, still with flat section assumption two-way bias of the normal section bearing capacity calculation formula is given.   由于多肢的存在,其截面的剪力中心往往在截面外,受力后主要依靠柱肢交點處的核心混凝土協調變形和傳遞內力,導致各柱肢內存在相當大的剪應力和翹曲應力,柱肢易首先出現裂縫,核心混凝土處于三向受剪狀態,變形能力降低,脆性破壞特征明顯

     As a result of the existence of multiple limbs, the cross section of shear center often outside the section, stress relies mainly on the column after limb intersection point of the core concrete coordination deformation and internal force, which caused a considerable in each column limb shear stress and warping stress of column limb first cracks easily, the core concrete in three-way shear condition, deformation is reduced, the characteristic of brittle failure is obvious.   異形柱的斜截面受剪承載力也隨荷載作用方向而變化,但對同一方向的地震作用由于翼緣的有利作用,通常比等面積矩形柱高,文獻【4】表明,T形截面柱的受剪承載力至少為同截面面積矩形柱的1.15倍,L形柱則基本相同

     Oblique section shear bearing capacity of special-shaped columns also varies with the loading direction, but in the same direction seismic action due to the effect of flange, are usually higher than such as area of rectangular column, literature 【4】 showed that the shear bearing capacity of t-shaped cross section column is to be at least 1.15 times with the cross section area of the rectangle column, l-shaped column is basically the same.   2.3節點強度 2.3 joint intensity   普通框架只要梁柱截面滿足規范構造要求,節點核心區面積大,除二級或更高抗震等級的節點外,一般不需要特別進行節點抗剪驗算

    但異形柱框架的肢厚不大,節點核心區有效水平截面積小

頭部信托-南水北調1號水庫項目非標政信

    另外,異形柱由于軸壓比的要求,通常肢長較大,相對同截面面積的矩形柱來講,剛度大,地震作用大,相應的節點剪力比相同布置下(柱面積相等)的矩形柱結構大很多

    因此異形柱框架節點一般都需要驗算節點抗剪強度

    同時,異形柱肢厚度偏薄,節點斜壓機制引起的核心區斜壓力相對較大,鋼筋握裹性能差,施工質量的可靠性也難以滿足

     General framework as long as meet the requirements of normative structure of column section and beam section, the shear area is large, besides seismic grade node level 2 or higher, generally do not need special node shear and checking. But not thick limb of special-shaped column frame, the shear level effective cross-sectional area is small. In addition, special-shaped columns because of axial compression ratio requirements, limb length is larger, usually relatively with the cross section area of the rectangular column, stiffness big, seismic action, the corresponding node shear (column area equal) than under the same arrangement of rectangular column structure. Therefore typically require checking special-shaped columns frame node shear strength. Special-shaped columns limb thickness slants thin, at the same time, the node core oblique pressure caused by baroclinic mechanism is opposite bigger, grip performance is poor, the reliability of the construction quality is difficult to meet.   異形柱截面形式的不同,其節點受剪承載力也差別較大

    十形截面柱的翼緣布置在節點截面中間受力最大的部位,翼緣的作用得以充分發揮,節點受剪承載力與同截面面積的矩形柱相差不大,T形截面次之,L形相差最大,受剪承載力下降最大

    文獻【5】研究表明:L形、T形、十形柱節點的受剪承載力比具有相同有效截面的矩形柱節點分別低33%、17.5%、8%左右,且用于矩形柱框架節點抗剪驗算的公式已不適用于異形柱節點

    在高烈度地區控制異形柱結構適用高度的參數已不單單是柱軸壓比,而是節點區的強度

     Special-shaped columns section form different, the shear bearing capacity difference is bigger also. Ten shaped cross section column flange arrangement among the nodes section largest stress parts, to give full play to the role of the flange, the shear bearing capacity with the same cross section area of the rectangular column were similar, t-shaped cross section, l-shaped biggest difference, shear bearing capacity drops is the largest. 【5】 research shows that: L, T, 10 column shear bearing capacity of node is more effective than with the same cross section of the rectangular column node low 33%, 17.5% and 33% respectively, and used in rectangular column frame node shear calculation formula is not suitable for special-shaped column nodes. In high intensity area control structure with special-shaped columns is the height of the parameter is not just the column axial compression ratio, but the node area strength. 3 構造措施 3 construction measures      異形柱的受力情況復雜,結構延性相對較差,單純依靠目前的程序計算配筋尚難滿足結構抗震的延性要求,因此必須加強構造措施,從概念出發,保證結構具有足夠的安全度

     Force of the special-shaped columns is complex, the relatively poor ductility of structure, relying on the current application of reinforcement calculation is difficult to satisfy the demands of structure seismic ductility, so must strengthen the construction measures, starting from the concept, to ensure that the structure has enough safety.   3.1結構平面布置 3.1 structure layout   異形柱框架應設計成雙向剛接梁柱抗側力體系,根據結構平面布置和受力特點,可設計成部分異形柱部分矩形柱的形式,特別注意在受力復雜部分采用矩形柱

    平面布置宜使結構平面剛度均勻對稱,盡量控制或減小扭轉效應:豎向布置注意體型力求簡單規則,避免過大的外挑內收,避免樓層剛度沿豎向突變;柱網尺寸不易過大,一般不超過6m,柱矩大梁高也大,一方面建筑凈空難以滿足要求,另一方面柱承受的軸力也大,軸壓比高,于抗震不利

    為保證梁板對異形柱節點的約束,宜采用現澆樓蓋

     Special-shaped columns frame should be designed as a two-way just answer Liang Zhukang lateral force system, according to the structure layout and mechanical characteristics, can be designed as part of the special-shaped columns section in the form of a rectangular column, special attention to in the complex loading using rectangular column. Layout appropriate uniform plane stiffness symmetry and try to control or reduce the reverse effect: vertical arrangement pay attention to the body to simple rules, avoid excessive outside carry adduction, avoid floor along the vertical stiffness mutation; Column grid size not too big, generally no more than 6 m, high column moment girder is big also, architectural headroom is difficult to meet the requirements on one hand, on the other hand column under axial force is big, high axial compression ratio, the seismic unfavorable. In order to ensure the beam slabs of special-shaped column node constraints, appropriate USES cast-in-place floor.   3.2軸壓比及柱配筋 3.2 axial compression ratio of column reinforcement   對于柱而言,控制其延性的因素很多,不管對矩形柱還是異形柱,軸壓比無疑是最重要的控制條件之一,其側移延性比隨著軸壓比的增大而急劇下降,對異形柱更應從嚴控制

    這可以通過控制柱距、采用輕質墻體、優化結構平面布置改善

    柱肢端承受梁傳來的集中荷載,局部壓應力大,可設置暗柱

    曹萬林等《鋼筋混凝土帶暗柱異形柱抗震性能試驗及分析》表明:帶暗柱異形柱與普通異形柱相比,承載力及延性和耗能能力有顯著提高

     For column, there are many factors which can control its ductility, whether for rectangular column or special-shaped columns, axial compression ratio is undoubtedly one of the most important control condition, the lateral ductility ratio fell sharply, with the increase of axial compression ratio of special-shaped columns should be strictly controlled. This can be achieved by control column space, use of lightweight wall layout improvement, optimization of structure. Column from acra beams under concentrated load, local compression stress is large, dark column can be set up. Cao Wanlin etc. The seismic performance of reinforced concrete special-shaped columns with dark column test and analysis show that the special-shaped column with dark column compared with the ordinary special-shaped columns, the bearing capacity and ductility and energy dissipation capacity has improved significantly.   異形柱截面的剪力中心與截面形心不重合,剪應力的存在使柱肢先于普通矩形柱的剪壓構件出現裂縫,產生腹剪破壞,導致柱脆性顯著,延性普遍低于矩形柱

    而且柱截面可能出現單純翼緣受壓,此時柱的延性最差,因此需要進一步提高異形柱的抗剪能力

    除此之外,盡量避免短柱的出現,對剪跨比小的短柱要采取相應的加強措施,以免形成薄弱環節

     Special-shaped columns section of the shear center and the section centroid is not coincidence, the existence of the shear stress of column limb ahead of ordinary rectangular column shear component cracks, generate shear failure, lead to post brittleness, ductility is generally lower than the rectangular column. And compression of column section may appear simple flange, the ductility of the column's worst right now, so you need to further improve the shear capacity of special-shaped columns. In addition, to avoid the occurrence of short column, the short column shear span ratio lower are the corresponding strengthening measures, so as to avoid formation of weak links.   3.3節點構造 3.3 joint structure      節點已經成為異形柱結構的薄弱環節,考慮到節點處鋼筋的錨固以及保證節點區混凝土澆筑的質量,柱鋼筋數量不宜過多且直徑不宜過大

     Node has become the weak link of special-shaped column structure, considering the node reinforcement anchorage and guarantee the quality of node area concrete pouring, column number is unfavorable and overmuch and diameter steel shoulds not be too big.      4 工程實例 4 engineering instance      長沙市某住宅樓長24.7m,寬14.5m,建筑面積3575m2左右,地上架空層一層,層高4.5m,住宅十一層,層高3.0m,最大建筑高度為39.0m,平面圖見圖1

    該工程抗震設防烈度為6度,設計基本地震加速度為0.05g,設計地震分組為第一組,場地類別Ⅱ類

    采用異形柱框架——剪力墻結構,剪力墻抗震等級為三級,異形柱框架抗震等級為三級

    采用SAIWE程序分析,各層間位移角見圖2,滿足規范對層間位移的規定;同時重視抗震概念設計,加強構造措施

    目前已竣工驗收交付使用,經觀察結構整體狀況良好

     A residential building in changsha city is 24.7 m long, 14.5 m, building area of 3575 m2, stilt floor layer on the ground, the height 4.5 m, residential 11 layer, the height 3.0 m, the largest building height is 39.0 m, the floor plan as shown in figure 1. The engineering seismic fortification intensity is 6 degrees, design basic earthquake acceleration of 0.05 g, design earthquake group is the first group, site category Ⅱ class. With frame - shear wall structure with special-shaped columns, the shear wall seismic grade for level 3, special-shaped column frame aseismic grade 3. SAIWE program analysis, by using the interlayer displacement Angle as shown in figure 2, and meet the specifications of the provisions of the interlayer displacement; At the same time attaches great importance to the seismic conceptual design, to strengthen the construction measures. Now consign is used, the final acceptance of the observed structure overall in good condition.      5 結語 5 conclusion      異形柱結構具有廣闊的應用前景,但其受力性能具有自己的獨特性,目前仍需要進一步研究以完善設計理論,開發更適用的設計軟件,提高工程設計效率,便于推廣運用

     Special-shaped column structure has broad application prospects, but its mechanical performance has its own uniqueness, still needs further research to perfect the design theory, more suitable design software development, improve the efficiency of engineering design, easy to promote.

文章版權及轉載聲明

作者:linbin123456本文地址:http://www.cocoon.org.cn/zhengxinxintuo/85996.html發布于 2023-12-01
文章轉載或復制請以超鏈接形式并注明出處城投定融網

閱讀
分享