DE10254043B4

DE10254043B4 - Composite construction of high load capacity

Info

Publication number: DE10254043B4
Application number: DE2002154043
Authority: DE
Inventors: Stefan Prof. Dr.-Ing. Winter
Original assignee: Universitaet Leipzig
Current assignee: WINTER, STEFAN, PROF.DR.-ING., 36341 LAUTERBAC, DE
Priority date: 2002-11-20
Filing date: 2002-11-20
Publication date: 2006-10-05
Anticipated expiration: 2022-11-21
Also published as: DE10254043A1

Abstract

composite structure high load capacity made of wood or wood-based material and concrete, in the case of wood or wood-based material and concrete flat are connected, wherein for the production of non-positive bond between wood or wood-based material and concrete profiled ribs Wood or wood-based material are used, with the wood or wood-based material are firmly connected and protrude into the concrete, and parallel to Main support direction of the composite cross-section, characterized in that the ribs profiling have an undercut and as exclusive Serve means for producing the wood-concrete composite.

Description

The This invention relates to wood / concrete composite structures, wood material / concrete composite structures and wood / wood-based material / concrete composite structures with high load capacity, For the production of high performance materials are used.

The Composite construction can be both in new construction as well as in the upgrade existing wood or wood-based material structures as load-bearing and / or room-closing Component be used. In bridge construction is a use as a load-bearing slab possible. Other applications result from the weight savings compared to standard constructions - possibly still reinforced through the use of lightweight concrete - for problematic subsoil, for increases or conversions.

When Components for Wood-concrete composite sections are normal concretes and already longer used solid woods known. For the interaction of the individual cross-sectional parts and thus for the load-bearing behavior Of the total composite cross-section of particular importance are the to be used connecting means. You decide about the Composite effect, the production cost and the cost of the whole Composite construction.

On In the field of wood-concrete composite construction are a variety of research results, property rights and publications and composite constructions used in practice available. However, is still not cheap, sufficiently ductile Lanyard has been found that is an economically interesting and competitive manufacturing of wood-concrete composite constructions allowed in large quantities and to the Use of the newly developed and now ready for use High performance concrete is adjusted.

The Causes of the disadvantages are as follows.

at slim, punctiform Lanyards such as screws, nails o. Ä. Result in a high number of connection points and thus a high production cost in situ. The possible Pre-fabrication grade is low because the fasteners are too slim are about the transport of several stacked To enable elements and there is a risk of damage during installation.

Farther to lead slim connecting means such as screws or nails under longitudinal thrust load due to relatively large Shifts between concrete and wood / wood material to a reduced Composite action. The carrying capacity of the composite cross-section including that of the composite effect resulting positive properties is reduced.

at punctual Arrangement of the connecting means result in different levels of stress the composite agent. The previously known slim fasteners are not ductile enough, i. the existing plastic deformation capacity is too low to force transfer to less stressed areas to reach. It follows a failure of the connecting means in the the highest stressed areas without the load capacity in less stressed Areas exhausted would. following Failure of the hitherto less stressed fasteners - the composite cross section "breaks" in the joint.

In the DE 298 24 534 U1 a board stack element is described, between the slats sheets or squared lumber are arranged, which protrude as webs in the concrete slab. The bond is made by "transverse force anchor", which are inserted into recesses of the webs. Even with this arrangement of the composite creates an approximate rigid composite, which means that the carrying capacity of the connecting means in initially less stressed areas can not be exploited by rearrangement of the stresses. An equidistant dowelling along the composite surface can not take place. In addition, the arrangement of the transverse force anchors in the protruding ribs running parallel to the main supporting direction leads to a transverse tensile stress on the wood and as a result to brittle failure.

From the DE 298 16 002 U1 is a wooden slab composite cover known in which the rigid bond between the pressure plate made of concrete and the wooden planks or

Wood material board strips by reinforced concrete strips or by profiled strips, which run at right angles to the ceiling tension direction, is realized. In this case, only the laid crosswise to the ceiling tension direction wooden strips obstruct the mutual displacement of wood and concrete layer and enforce a common supporting effect of the cross-sectional parts. Another disadvantage of this composite design is also in the resulting from the rigid composite arrangement of the connecting means, which are coupled to the thrust force profile. From an economic point of view, the offsets running at right angles to the clamping direction must be arranged at variable distances. When the offsets are placed at a constant pitch, the utilization rate is much lower.

at All the above solutions is also characterized by the use of only normal concrete between Concrete and wooden component to install a moisture protection layer, what leads to high costs and is not very robust in construction site operation.

aim The invention is the creation of a less labor-intensive in the production and robust, flat Composite between concrete and wood / wood-based material, around one To achieve composite cross-section with improved load capacity and the Cost and time compared to reduce the known method. Should arise a variable usable and easy to handle construction for universal Areas of responsibility which have a high degree of prefabrication and can be performed with high-strength and normal concretes.

at problematic ground or when building in stock is a reduction the self-load share of the construction makes sense. The by the use By wood already achieved weight saving should by the use high-strength or lightweight concrete to be reinforced.

There will be a Composite requires, that is sufficiently ductile and equidistant can be arranged. At the same time an industrial prefabrication possible be without the individual adaptability, especially when building in stock or at unusual Geometry is essential is to affect. These mentioned features are intended for easy handling the construction site and to rationalize the construction process and thus to a damping lead the construction costs.

Furthermore must be the lanyard for be suitable for the use of all types of concrete.

Therefore the invention has the task of a shear-resistant composite between to ensure the concrete and a wood / wood-based material layer. It should be a durable and stable surface bond between concrete and wood reliable be achieved. Furthermore, the more recently available High-performance concretes as well as newly developed solid wood and wooden materials with significantly improved mechanical properties tested and at Success be used. It should be the "zipper effect" by a qualified Arrangement of the connecting means according to the flow of forces or even with equal intervals be avoided by a highly ductile bonding agent.

The The object is achieved according to the invention as follows.

It a composite cross-section is created, made of wood or wood-based material and concrete, the latter being normal concrete or high performance concrete can be. Between the wood or wooden material layer and the Concrete layer are profiled ribs arranged in the concrete slab protrude and with the wood or wood-based material by connecting means are firmly connected. The ribs are made of wood or wood materials and run parallel to the main support direction of the composite cross section Die Geometry of the ribs has a profiling undercut on, that is a negative slope.

Of the Invention is based on the finding that the asked solve a task lets go embedded in the concrete profiled ribs by means of pin-shaped connecting means or gluing frictionally connected to the wood / wood material.

Tilt and shaping the ribs, for example, concave, convex or variable Tilt angle, can be modified, modified or supplemented. additionally An end anchorage can be provided. This can be done by a only at the end of the rib deviating shape, by additionally transverse and / or along inserted reinforcing bars and / or by additional composite means such as screws or steel angle.

The Parts of the composite construction can be individually be processed on site as a prefabricated construction or as a partially prefabricated construction with on a support plate combined ribs are applied.

The Composite effect arises from the undercut of the ribs. The result following clamping effect between ribs and concrete leads to an activation the frictional forces and represents a plane Composite between concrete and wooden component in the supporting direction ago. The resulting joint supporting action of the cross-sectional parts as composite cross section leads to those already listed Benefits.

The geometric shape and the arrangement of the ribs parallel to the supporting direction of the composite cross-section force a common longitudinal displacement all fasteners. In addition to the high ductility in the Compound joint results from this the possibility of connecting means equidistant in the rib, So with constant distances independent of Course of the longitudinal thrust to arrange. If necessary, an additional end anchorage is required.

The Longitudinal thrust forces can either by means of a pin-shaped Connecting means (e.g., screws, nails, etc.) and / or transferred by adhesive be, the pulling forces at right angles to the compound joint are made by pin or screw-type fasteners transferred into the wood or wooden material surfaces. Become the ribs claimed due to their fiber flow on transverse train, these serve Lanyard in addition as a transverse tensile reinforcement.

If you can use screws, the adhesion can be increased, if they have two threads with different pitch. The arrangement of the pin-shaped Connecting means is possible both inclined and vertical. The called pin-shaped Lanyards can also nails, Anchors, dowels, Clamps, bolts or the like.

at the production of the composite construction including its Cross-sectional parts are a high degree of prefabrication and the industrial Manufacturing possible. The connecting means between ribs and wood / wood material will be mechanically protected by the sturdier ribs. This is both the production on the construction site as well as the prefabrication and transport of Semi-finished parts and finished parts possible. Semi-finished parts exist made of elemental wood components, e.g. Board stack elements or Veneer plywood panels with already applied ribs. The Concreting and, if necessary, the introduction of the reinforcement then takes place on site (only required for semi-finished parts). Own the finished parts already a wood / wood material-concrete cross-section.

by virtue of The elementation and easy adaptability of the system are individual solutions possible. The reduction of the assembly time leads to a better weather insensitivity and thus also a higher one Construction quality of construction. Industrial quality assurance procedures become applicable. By simplifying the construction process will be on-site sources of error eliminated.

Of the Planner now has the option to design a design oriented to the requirements. Thus, e.g. If necessary, the pressing action between screwed Rib and the wood or wood-based component by screws with be reinforced two threads of different pitch.

By An optimization of the layer thicknesses and their strengths can be the Zero-line be adjusted so that the wood-based material layer the tensile forces and the concrete layer takes over the pressure forces. In certain circumstances thus a reinforcement of the concrete layer can be avoided.

The Concrete layer can be made of normal concrete or a high-performance concrete like self-compacting concrete, self-compacting lightweight concrete, high-strength Concrete, fiber concrete or the like exist.

The invention will be explained in more detail with reference to embodiments and figures. A general perspective view is in 1 , The composite cross-section is produced by the shear-resistant connection of the concrete slab to the wood / wood-based panel. The force transmission between concrete slab and rib is always ensured by the undercut geometry ( 7 . 8th ). In contrast, the connecting means in the joint between rib and wood / wood-based panel is variable. Frictional forces are activated due to the undercut geometry of the ribs. The resulting longitudinal thrust and traction forces must be absorbed by the connecting means.
at the subsequent Concreting the wood element can be used simultaneously as a formwork.
Example 1: ( 3 )
Benefited ribs ( 2 ) according to 7 respectively. 8th be on a wooden part ( 3 ) such as board stacking element, veneer plywood panel attached. As connecting means are pin-shaped connecting means ( 4 ), as in 9 and 10 used, which simultaneously absorb the longitudinal thrust and tensile forces. The wood layers) bear together with the concrete layer and serve as formwork during the concreting process.
Example 2: ( 4 )
For the wood layer ( 3 ) thick-gauge wood is used, the top layer is milled rib-shaped. Alternatively, between ribs ( 2 ) and wood / wood-based panel ( 3 ) a non-positive adhesive joint ( 5 ), which receives the longitudinal thrust forces. The tensile forces can also be achieved by pin-shaped connecting means ( 9 . 10 ), which simultaneously form the transverse tensile reinforcement for the rib profile.
Application as a composite ceiling in building construction or as a load-bearing slab in bridge construction: ( 1 )
horizontal Installation position of a wood-concrete composite construction
Application as composite wall: ( 2 )
Vertical installation position of the composite cross-section, which in this case has a three-layer structure. The outer surfaces are made of two wood or wood board ( 3 ) with ribs attached thereto ( 2 ) educated. The gap is cavity-free with reinforced or unreinforced concrete ( 1 ).
The to the embodiment belonging pictures demonstrate:
1 perspective views of the composite cross-section in horizontal mounting position, general presentation (connecting means not shown)
2 perspective view of the composite cross-section in vertical mounting position, general presentation (connection means not shown)
3 Composite cross-section, example 1: ribs screwed on wood layer (eg board stacking element, solid wood or wood-based panel)
4 Composite cross-section, Example 2: ribs in the uppermost layer of thick-film wood milled and glued, pin-shaped fasteners transmit only tensile forces
5 Longitudinal section through composite cross-section, pin-shaped connection means installed below 90 °
6 Longitudinal section through composite cross-section, pin-shaped connecting means mounted inclined
7 possible profile shapes of the rib
8th different arrangement of the ribs: single rib or combined on a carrier plate (pin-shaped connecting means in the carrier plate for receiving the tensile forces not shown)
9 pin-shaped connecting means (screw forms)
10 pin-shaped connection means (clamps, screws, nails)

Claims

Composite construction of high load-bearing capacity made of wood or wood material and concrete, in which wood or wood material and concrete are connected flat, wherein profiled ribs of wood or wood material are used to produce the non-positive bond between wood or wood material and concrete, which firmly connected to the wood or wood material are and project into the concrete, and parallel to the main support direction of the composite cross-section, characterized in that the ribs have a profiling undercut and serve as the exclusive means for producing the wood-concrete composite.
Composite construction according to claim 1, characterized that the ribs have an end anchorage.
Composite construction according to claim 1 or 2, characterized in that it has connecting means for connecting the ribs with the flat wood or Wooden material construction which are formed pin-shaped.
Composite construction according to claim 1 or 2, characterized in that it has connecting means for connecting the ribs with the plane Wood or wood-based construction, which is helical are and the helical ones Embodiment has different threads.
Composite construction according to one of claims 1-4, characterized characterized in that the ribs with the flat wood or the flat wood material construction are glued.
Composite construction according to one of claims 1-5, characterized characterized in that the concrete is either a normal concrete or a High performance concrete is.
Composite construction according to any one of claims 1-6, thereby characterized in that it is prefabricated.