JP3709080B2

JP3709080B2 - String string structure

Info

Publication number: JP3709080B2
Application number: JP30405798A
Authority: JP
Inventors: 昭穂原田; 徹竹内; 博志中村
Original assignee: Nippon Steel Corp
Current assignee: Nippon Steel Corp
Priority date: 1998-10-26
Filing date: 1998-10-26
Publication date: 2005-10-19
Anticipated expiration: 2018-10-26
Also published as: JP2000129859A

Description

【０００１】
【発明の属する技術分野】
本発明は、土木・建築分野における屋根構造等において使用される張弦梁構造に関するものである。
【０００２】
【従来の技術】
従来の土木・建築分野で用いられてきた張弦梁構造としては、図６に示すように上方向に凸な圧縮上弦材１と下方向に凸な引張下弦材４とを組み合わせ、両者を一定間隔の束材３で連結して両端で支持構造６により支持することにより、屋根面に下向きに加わる自重や積載荷重などの均等荷重に対して全体が抵抗するように構成されたものが挙げられる。不均等荷重に対しては、必要に応じて斜め引張材５を付加することもある。この場合、図７に示す事例（「新建築」１９９７年５月号１１６ページ）に見るように、圧縮上弦材１には鋼管、Ｈ型鋼などを用い、横方向につなぎ材１０で連結して安定させるのが一般的である。
【０００３】
屋根構造の例としては、この他、特開平７−１９７５８３号公報に示されるように、多数のテンション材を縦横にかつ交互に組み重ねて張り込み格子状の上部屋根組および下部屋根組として上下２重に配置したものもある。しかし、これは上下のテンション材とも緊張するもので、前記張弦梁構造とは異なるものである。
【０００４】
【発明が解決しようとする課題】
前記従来の張弦梁構造においては、横方向につなぎ材１０を連結するまで屋根構造全体が安定せず、建て方の途中段階では屋根構造を安定させるため張弦梁構造を支える仮設材が必要であるという課題があった。また、構造材の組み立てや屋根工事に伴い、作業員が所定の場所に行くための仮設足場が多く必要になるという課題もあった。
【０００５】
なお、特開平６−１３６８２８号公報には、一個の張弦梁構造が横方向の仮設材なしに自立するかのような例が図示されている。しかし、この例は上方へ湾曲する張弦材自体が一定の幅を有して屋根となるものであり、しかもその屋根となる張弦材の幅方向両側端から垂設した第２の索状体を基礎構造体に設けた引留部へ固定し、緊張力を付与することが必須とされている。したがって、同例は、図６に示したようなそれ自体が屋根となるものではない張弦梁構造を用いて図７に示したような屋根構造を構築する際の前述の課題を解決する手段になり得るものではない。
【０００６】
本発明の目的は、この張弦梁構造において、建て方の途中段階で屋根構造を安定させる仮設材を不要とし、かつ作業員が所定の場所に行くための仮設足場を省略できる構造を提供することにある。
【０００７】
【課題を解決するための手段】
本発明の張弦梁構造は、２本の外側に湾曲した圧縮上弦材１を間隔を空けて並べ、両者間を連結材２である間隔ごとに連結して梯子状上弦部を構成し、連結材２の一部または全部の中央下方向に束材３を固着し、束材３の下端部と梯子状上弦部の両端部とを引張下弦材４で連結し、上下弦材と交差する方向のつなぎ材なしで転倒せずに自立することができることを特徴とする張弦梁構造である。この場合、前記張弦梁構造が両端で支持された状態で仮設時または完成後に受ける荷重に対し、前記梯子状上弦部が自立するだけの水平方向剛性および耐力を有していることが好ましい。また、前記本発明の張弦梁構造をある間隔で並べ、梯子状上弦部を圧縮上弦材７で、束材下端部を引張下弦材８で直交方向に連結し、直交方向にも張弦梁を構成することが可能である。
【０００８】
本発明の張弦梁構造では、圧縮上弦材１を梯子状に組む、すなわち２本の圧縮上弦材１を間隔を空けて並べ、両者間を連結材２である間隔ごとに連結することによって梯子状上弦部を構成する。これにより、張弦梁構造の横方向の耐力および剛性が向上し、横方向のつなぎ材なしで自立できるようになる。その結果、建て方の途中段階で構造を安定させるための仮設材を省略することができ、各張弦梁構造を地上で組み立て、梁毎に直接支持点間に重機等で吊り込むことが可能となる。
【０００９】
また、支持点間に架け渡された本発明の張弦梁構造は、上部が幅のある梯子状上弦部よりなっているため、作業員が容易にその上を移動することができ、２次部材や屋根材などの工事を行う上で必要となる仮設足場を大幅に省略することができる。
【００１０】
さらに、前述の本発明の張弦梁構造をある間隔で並べ、これらを直交方向に圧縮上弦材と引張下弦材で連結すれば、縦横両方向に張弦梁を構成した張弦梁構造となる。
【００１１】
【実施例】
次に本発明を図示の実施例によって詳細に説明する。
【００１２】
図１は本発明の張弦梁構造を用いた屋根構造の例を示す図であって、図２はそのＡ−Ａ′断面図である。２本のＨ型断面を持つ圧縮上弦材１が水平方向に間隔を持って並び、両者がＨ型断面の連結材２によって一定間隔で連結されて梯子状上弦部を構成している。一部の連結材２の中央より下方向に向かって鋼管の束材３が固着され、束材３の下端部および梯子状上弦部の両端が２本の引張下弦材４によって連結され、全体が両端で支持構造６によって支持されて張弦梁構造を構成している。また、不均等荷重に対する変形を抑えるため、必要に応じて斜め引張材５を追加することもできる。
【００１３】
図３は５０ｍのスパンを持つ本発明の張弦梁構造の部材設計例を示す図であって、図４はそのＡ−Ａ′断面図である。建て方時に屋根構造にかかる鉛直荷重を８０ｋｇ／ｍ²とすると、梯子状上弦部にかかる軸力Ｎおよび曲げモーメントＭは解析によりそれぞれ約４３ｔ、２．３ｔｍとなる。梯子状上弦部の座屈長は、日本建築学会発行「鋼構造設計基準」により数１となる。
【００１４】
【数１】
全体座屈長λ_y＝２Ｌ／Ｂ＝２×５０００／８０＝１２５
個材座屈長λ_l＝Ｌ_l／ｉ_l＝３１２．５／５．０２＝６２
梯子状上弦部等価座屈長λ_e＝√（λ_y ² ＋λ_l ²）＝１４０
ここに、Ｌ：全体スパン長（ｃｍ）
Ｂ：圧縮上弦材間隔（ｃｍ）
Ｌ_l ：連結材間隔（ｃｍ）
ｉ_l ：圧縮上弦材最小断面２次半径（ｃｍ）
【００１５】
これより、圧縮上弦材の許容圧縮応力度ｆ_cは０．４８８ｔ／ｃｍ²（ＳＭ４９０鋼の場合）となり、梯子状上弦部の設計チェック値は数２となり、該張弦梁構造は建て方時の荷重に対し横方向に安定し、仮設材なしで自立することが確認できる。
【００１６】
【数２】

ここに、Ｚ_x：圧縮上弦材の断面係数（ｃｍ）
ｆ_b：圧縮上弦材の許容曲げ応力度（ｔ／ｃｍ²）
【００１７】
上記計算例では、梯子状上弦部を建て方時の荷重に対し自立するように設計しているが、同様の計算で建物完成後の荷重に対して自立するように設計することも可能である。この場合は、完成後もつなぎ材や母屋を省略することが可能となる。
【００１８】
以上の例において、圧縮上弦材１の断面は、Ｈ型以外にも鋼管、［型、Ｌ型、鋼棒など任意の断面を使用することが可能であり、また素材についても、鋼材以外に木材、コンクリートなど任意の素材を使用することができる。これは束材３についても同様である。また、引張下弦材４についても、ワイヤー、鋼棒、鋼板など任意の断面および素材を使用することができる。
【００１９】
図５は、張弦梁構造を直交方向に連結して縦横に張弦梁を構成した張弦梁構造を用いた屋根構造の例を示す図である。前述のように２本の圧縮上弦材１が連結材２で連結された梯子状上弦部を持つ第１の張弦梁構造を一方向にある間隔で並べ、梯子状上弦部を直交方向の圧縮上弦材７によって連結し、束材３の下端部を直交方向の引張下弦材８によって連結し、結果的に直交方向にも第２の張弦梁構造が構成されている。このような立体張弦梁構造においても、一方向を梯子状上弦部を有する張弦梁構造とすることによって、第１の張弦梁構造を地上で組み立て重機などで支持構造上に吊り込み、これを足場代わりにして直交方向の圧縮上弦材７、引張下弦材８を挿入していく手順を踏むことが可能となり、仮設材および仮設足場を大幅に省略した建て方を行うことができる。
【００２０】
【発明の効果】
本発明により、張弦梁構造が横方向のつなぎ材なしで自立することになるので、建て方の途中段階で屋根構造を安定させる仮設材を不要とし、かつ作業員が所定の場所に行くための仮設足場を省略することが可能となる。
【図面の簡単な説明】
【図１】本発明の張弦梁構造を用いた屋根構造の例を示す図である。
【図２】図１のＡ−Ａ′断面図である。
【図３】本発明の張弦梁構造の部材設計例を示す図である。
【図４】図３のＡ−Ａ′断面図である。
【図５】縦横に張弦梁を構成した張弦梁構造を用いた屋根構造の例を示す図である。
【図６】従来の張弦梁構造の例を示す図である。
【図７】従来の張弦梁構造を用いた屋根構造の例を示す図である。
【符号の説明】
１圧縮上弦材
２連結材
３束材
４引張下弦材
５斜め引張材
６支持構造
７圧縮上弦材
８引張下弦材
９母屋
１０つなぎ材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stringed beam structure used in a roof structure or the like in the civil engineering / architectural field.
[0002]
[Prior art]
As shown in FIG. 6, the tension string structure that has been used in the conventional civil engineering / architecture field is a combination of a compression upper chord member 1 that protrudes upward and a tension lower chord member 4 that protrudes downward, which are spaced apart at a fixed interval. By connecting with the bundle material 3 and supporting it with the support structure 6 at both ends, the entire structure can be resisted against a uniform load such as its own weight or a loaded load applied downward on the roof surface. The oblique tension material 5 may be added to the uneven load as necessary. In this case, as shown in the example shown in FIG. 7 (“New Architecture”, May, 1997, page 116), the compression upper chord material 1 is made of steel pipe, H-shaped steel, etc., and is connected by a connecting material 10 in the lateral direction. It is common to stabilize.
[0003]
As an example of the roof structure, as shown in Japanese Patent Application Laid-Open No. 7-197583, a number of tension members are stacked vertically and horizontally and alternately stacked to form an upper roof group and a lower roof group in the form of a lattice. Some are arranged in layers. However, this is a tension between the upper and lower tension members, and is different from the above-mentioned stringed beam structure.
[0004]
[Problems to be solved by the invention]
In the conventional stringed beam structure, the entire roof structure is not stabilized until the connecting material 10 is connected in the lateral direction, and a temporary material is required to support the stringed beam structure in order to stabilize the roof structure in the middle of the building. was there. In addition, there has been a problem that a lot of temporary scaffolds are required for workers to go to a predetermined place along with assembly of structural materials and roof construction.
[0005]
Japanese Patent Laid-Open No. 6-136828 discloses an example in which a single stringed beam structure is self-supporting without a temporary material in the lateral direction. However, in this example, the stringed material that curves upward is itself a roof having a certain width, and the second cord-like body suspended from both ends in the width direction of the stringed material that forms the roof is the basic structure. It is indispensable to fix the tensioning part provided on the body and to give tension. Therefore, this example is a means for solving the above-described problem in constructing a roof structure as shown in FIG. 7 using a stringed beam structure that is not itself a roof as shown in FIG. Not what you get.
[0006]
An object of the present invention is to provide a structure that eliminates the need for a temporary material for stabilizing the roof structure in the middle of the building and eliminates a temporary scaffold for an operator to go to a predetermined place in the stringed beam structure. is there.
[0007]
[Means for Solving the Problems]
In the stringed beam structure of the present invention, two compression upper chord members 1 curved outward are arranged at intervals, and the two are connected at intervals corresponding to the connecting member 2 to form a ladder-like upper chord portion. The bundle member 3 is fixed to the lower part of the center of a part or the whole, and the lower end portion of the bundle member 3 and both ends of the ladder-like upper chord portion are connected by the tensile lower chord member 4 and connected in the direction intersecting the upper and lower chord members. It is a stringed beam structure characterized in that it can stand on its own without falling down without a material . In this case, it is preferable that the ladder-like upper chord portion has a horizontal rigidity and a proof strength that allow the ladder-like upper chord portion to stand by itself with respect to a load received at the time of temporary installation or after completion in a state where the stringed beam structure is supported at both ends. Further, the stringed string structure of the present invention is arranged at a certain interval, the ladder-like upper chord part is connected with the compression upper chord material 7 and the bundle lower end part is connected with the lower tension chord material 8 in the orthogonal direction, and the stringed beam is also formed in the orthogonal direction. Is possible.
[0008]
In the stringed string structure of the present invention, the compression upper chord material 1 is assembled in a ladder shape, that is, the two compression upper chord materials 1 are arranged at intervals, and the two are connected at intervals corresponding to the connecting material 2 to thereby form a ladder upper chord. Parts. As a result, the lateral strength and rigidity of the stringed beam structure are improved, and it becomes possible to stand on its own without a connecting member in the lateral direction. As a result, it is possible to omit temporary materials for stabilizing the structure in the middle of the construction process, and it is possible to assemble each stringed beam structure on the ground and suspend each beam directly between the support points with a heavy machine or the like. .
[0009]
In addition, the stringed beam structure of the present invention spanned between the support points is composed of a ladder-like upper chord portion having a wide upper portion, so that an operator can easily move on the secondary member or Temporary scaffolding required for construction work such as roofing materials can be greatly omitted.
[0010]
Furthermore, if the above-described stringed beam structures of the present invention are arranged at a certain interval and these are connected in the orthogonal direction by a compression upper string material and a tension lower string material, a stringed beam structure in which the stringed beam is configured in both vertical and horizontal directions is obtained.
[0011]
【Example】
Next, the present invention will be described in detail with reference to illustrated embodiments.
[0012]
FIG. 1 is a view showing an example of a roof structure using the stringed beam structure of the present invention, and FIG. 2 is a sectional view taken along the line AA ′. Two compressed upper chord members 1 having an H-shaped cross section are arranged at intervals in the horizontal direction, and both are connected at a predetermined interval by a connecting member 2 having an H-shaped cross section to constitute a ladder-like upper chord portion. A bundle 3 of steel pipes is fixed downward from the center of some of the connecting members 2, and both ends of the lower end of the bundle 3 and the ladder-like upper chord are connected by two tensile lower chords 4. It is supported by the support structure 6 at both ends to form a stringed beam structure. Moreover, in order to suppress the deformation | transformation with respect to an uneven load, the diagonal tension | tensile_strength material 5 can also be added as needed.
[0013]
FIG. 3 is a diagram showing a member design example of the stringed beam structure of the present invention having a span of 50 m, and FIG. If the vertical load applied to the roof structure at the time of building is 80 kg / m ² , the axial force N and the bending moment M applied to the ladder-like upper chord are about 43 t and 2.3 tm, respectively, by analysis. The buckling length of the ladder-like upper chord part is given by Equation 1 according to the “Design Standards for Steel Structures” published by the Architectural Institute of Japan.
[0014]
[Expression 1]
Overall buckling length λ _y = 2L / B = 2 × 5000/80 = 125
Individual material buckling length λ _l = L _l / i _l = 312.5 / 5.02 = 62
Ladder-like upper chord equivalent buckling length λ _e = √ (λ _y ² + λ _l ² ) = 140
Where L: Overall span length (cm)
B: Compression upper chord material interval (cm)
L _l : Linking material interval (cm)
i _l : compression upper chord material minimum section secondary radius (cm)
[0015]
Than this, the allowable compressive stress of f _c of the compression top chord member (in the case of SM490 steel) 0.488t / cm ^2, and the design check value is the number 2 next to the ladder top chord section,該張Tsuruhari structure loads way when built In contrast, it can be confirmed that it is stable in the lateral direction and is independent without temporary materials.
[0016]
[Expression 2]

Where Z _x : section modulus (cm) of compression upper chord material
f _b : Permissible bending stress degree of compression upper chord material (t / cm ² )
[0017]
In the above calculation example, the ladder-like upper chord part is designed to stand up to the load at the time of building, but it can be designed to stand up to the load after the building is completed by the same calculation. . In this case, it is possible to omit the connecting material and the purlin after completion.
[0018]
In the above example, the cross section of the compression upper chord material 1 can be any cross section such as a steel pipe, [die, L type, steel bar, etc. in addition to the H type. Any material such as concrete can be used. The same applies to the bundle 3. Moreover, also about the tension lower chord material 4, arbitrary cross sections and raw materials, such as a wire, a steel bar, and a steel plate, can be used.
[0019]
FIG. 5 is a diagram showing an example of a roof structure using a stringed beam structure in which stringed beam structures are connected in the orthogonal direction to form the stringed beam vertically and horizontally. As described above, the first chord beam structure having the ladder-like upper chord portion in which the two compression upper chord members 1 are connected by the connecting member 2 is arranged at an interval in one direction, and the ladder-like upper chord portion is compressed in the orthogonal direction. 7, and the lower ends of the bundle members 3 are connected by a tension lower chord member 8 in the orthogonal direction, and as a result, a second stringed beam structure is also formed in the orthogonal direction. Even in such a three-dimensional stringed beam structure, the first stringed string structure is suspended on a support structure by a heavy machine or the like by assembling on the ground by using a stringed string structure having a ladder-like upper chord part in one direction, and using this as a scaffold The procedure of inserting the compression upper chord material 7 and the tension lower chord material 8 in the orthogonal direction can be taken, and a construction method in which the temporary material and the temporary scaffolding are largely omitted can be performed.
[0020]
【The invention's effect】
According to the present invention, the stringed beam structure is self-supporting without a connecting member in the horizontal direction, so that a temporary material for stabilizing the roof structure is not required in the middle of the construction, and a temporary structure for an operator to go to a predetermined place. Scaffolding can be omitted.
[Brief description of the drawings]
FIG. 1 is a view showing an example of a roof structure using a stringed beam structure of the present invention.
2 is a cross-sectional view taken along the line AA ′ of FIG.
FIG. 3 is a diagram showing a member design example of a stringed beam structure of the present invention.
4 is a cross-sectional view taken along the line AA ′ of FIG. 3. FIG.
FIG. 5 is a view showing an example of a roof structure using a stringed beam structure in which stringed beams are formed vertically and horizontally.
FIG. 6 is a diagram showing an example of a conventional stringed beam structure.
FIG. 7 is a diagram showing an example of a roof structure using a conventional stringed beam structure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Compression upper chord material 2 Connecting material 3 Bundle material 4 Tension lower chord material 5 Diagonal tension material 6 Support structure 7 Compression upper chord material 8 Tension lower chord material 9 Purlin 10 Tie material

Claims

Two outer compressed upper chord members 1 are arranged at intervals, and the two are connected at intervals corresponding to the connecting members 2 to form a ladder-like upper chord portion. The bundle member 3 is fixed in the downward direction, and the lower end portion of the bundle member 3 and both end portions of the ladder-like upper chord portion are connected by the tension lower chord member 4 without falling down without the connecting member in the direction intersecting the upper and lower chord members. A stringed beam structure characterized by being able to stand by itself .

2. The stringed beam structure according to claim 1, wherein the stringed string structure has horizontal rigidity and proof strength that the ladder-like upper chord part is self-supporting with respect to a load received during temporary installation or after completion in a state where the stringed beam structure is supported at both ends.

3. The stringed beam structure according to claim 1 or 2 is arranged at a certain interval, the ladder-like upper chord part is connected to the compression upper chord material 7 and the bundle lower end part is connected to the pulling lower chord material 8 in the orthogonal direction, and the stringed beam is also formed in the orthogonal direction. A stringed string structure characterized by that.