The invention relates to a prestressed engineered wood building construction system which provides protection against extreme loading events such as seismic events or high wind loading or exceptional gravity loading on the building.
Over approximately the last decade there has been increased work on the design and development of construction systems for multi-storey concrete and steel buildings for regions subject to seismic activity, which not only prevent catastrophic failure of the building and protect life, but which also enable buildings to withstand earthquakes without structural damage, so as to reduce the economic cost of building repair and/or reconstruction as well as minimising business interruption (downtime) after an earthquake.
In some cases very strong winds including cyclones can also cause building movement and structural damage.
The invention provides an improved or at least alternative construction system for a building which provides at least a degree of protection against seismic and/or wind loading events, with the objective of avoiding or minimising structural damage to the building following such a loading event.
In broad terms in one aspect the invention comprises a building which includes:
a connection between an engineered wood load bearing element of the building and another load bearing element or a foundation of the building,
at least one tendon tying the load bearing elements or the load bearing element and the foundation together, and
at least one energy dissipater replaceably connected between the load bearing elements or load bearing element and the foundation, which will absorb energy from a loading event causing relative movement of the connection.
In one form the building comprises two or more storeys. In another form the building comprises a single storey.
In a preferred form the energy dissipater is connected between the load bearing elements or the load bearing element and the foundation externally as will be further described.
Typically the load bearing element or elements is/are one or more structural elements of the building such as beams, columns, or walls. Alternatively the load bearing elements may be floor panels, which also bear load. The floor panels may or may not be supported by beams and/or columns and/or walls. Lateral load resisting systems consist of frames (of beams and columns fixed to each other, with the columns fixed to the foundations), or walls (fixed to the foundations), or combinations of frames and walls. The floors tie the walls or frames to each other, and are supported on beams and/or columns and/or walls.
Thus the connection may be a beam to column connection such as a beam to column connection between one beam and one column, a beam to column connection between a column and beams on two opposite (or more) sides of the column, or a corner beam to column connection with two beams connected to a column and extending in different directions from the column. The term “beam” should be understood in this specification to include a load bearing element whether horizontal or at an angle to be horizontal, which supports a roof, such as a roof-supporting structural element commonly referred to as a roof truss for example. Alternatively the connection may be a column to foundation connection, a wall to foundation connection where the wall element is a load bearing element, or a connection between adjacent wall elements such as wall panels where the wall panels are load bearing elements, or a wall to beam connection, in a separated wall assembly accompanying beams between the walls for example, or a floor panel to beam or column or wall connection.
Typically the engineered wood beam, column or panel is of laminated veneer lumber (LVL). By a laminated veneer lumber element it is meant a beam, column or panel produced by bonding together wood veneers or layers of up to about 10 millimeters in thickness with the grain of at least the majority of the veneers extending generally in the longitudinal direction of the beam column or panel. Alternatively the engineered wood element may be a parallel strand lumber element. By a parallel strand lumber element is meant an element consisting of long veneer strands, at least the majority of which are laid in parallel, bonded together to form the element.
Alternatively the element may be a glue laminated timber element, by which is meant an element consisting of individual pieces of lumber having a thickness typically from about 10 to about 50 mm, end-joined together to create longer lengths which are in turn laminated together to form the element.
The connection or connections is/are tied together by one or more tendons. Preferably the tendons are unbonded (not fixed) to the elements along the length of the element, but they may be partially bonded by being fixed to the element(s) at spaced intervals. The tendons may be straight or may change direction along the elements. Typically the tendon(s) pre-stress the elements and the joint.
One or more dissipaters are replaceably connected between the elements at the connection(s), enabling the sacrificial dissipater or the functional component thereof which yields in tension or compression or bending to be replaced after a seismic or extreme wind loading event for example. Preferably the energy dissipater is fixed to the exterior of the elements as will be further described but alternatively the energy dissipater may be mounted within a bore or cavity internally between the connected wood elements, in such a way as to enable the dissipater or a major functional part thereof to be removed and replaced.
During a seismic or extreme wind event of sufficient magnitude, controlled rocking motion occurs at the connection(s). For example a column or vertical load bearing wall panel connected to a base foundation in accordance with the invention may rock, or rocking may occur at a beam to column connection. During the rocking motion energy is dissipated by deformation of the replaceable energy dissipater while the tendons hold the connections together and self-centre or restore the connected elements to their original positions relative to one another at the conclusion of motion. Then the energy dissipaters may be replaced without requiring replacement of the engineered wood load bearing elements.
In one form the dissipater or dissipaters each comprise two plates fixed one to each of adjacent faces of two connected load bearing elements a bracket fixed to at least one plate or brackets fixed one to each plate or to and through each plate to the load bearing element, the brackets having a footprint on a face of the plate smaller than the area of the face of the plate, and a functional part connected between the load bearing elements via the bracket or brackets which will deform to absorb energy during seismic motion. In a preferred form the functional part comprises a longitudinally extending element which is removably fixed at its either end to the bracket(s). Alternatively the dissipater may be a bending element or a large number of fasteners such as nails.
The term ‘comprising’ as used in this specification and claims means ‘consisting at least in part of’, that is to say when interrupting independent claims including that term, the features prefaced by that term in each claim will need to be present but other features can also be present.
The invention is further described with reference to the accompanying figures which show various embodiments of the invention by way of example and without intending to be limiting. In the figures:
a-d show one form of energy dissipater for use between adjacent wall panels,
a-e show alternative forms of dissipaters for use between adjacent wall panels,
a and 9b show one form of dissipater in more detail,
Energy dissipation devices or dissipaters D are provided in between the longitudinal edges of adjacent wall panels P. The energy dissipation devices D are accessible from at least one side of the wall panels so that they can be replaced after a seismic or other loading event without requiring removal or replacement of the panels P. Energy dissipaters E (shown in
During such rocking motion the energy dissipaters D and dissipaters E if provided absorb energy, typically by deformation of the dissipaters or a functional part thereof. The dissipaters damp motion between the load bearing elements. The dissipaters may be in any form which will absorb energy, typically through yielding of the dissipater or a functional component thereof by bending for example. Alternatively the dissipater(s) may absorb energy via friction sliding between two parts of the dissipater, or viscous damping action. The tendons T tie the load bearing panels P in place but allow the rocking motion to occur during a loading event of sufficient magnitude. After the loading event the dissipaters may be replaced if necessary, without requiring removal or replacement of the panels P. Typically the dissipaters are accessible from the exterior of the panels (examples are described subsequently) enabling the dissipaters to be unfixed, removed and replacement dissipaters fixed in place readily. Alternatively the dissipaters may be mounted within a cavity internally between the connected load bearing elements, such as a cavity between edges of adjacent panels P, in such a way as to enable the dissipater or the major functional part of the dissipater to be accessed and removed and replaced after a loading event The tendons T may if necessary be re-tensioned, if the tendons have stretched during the rocking motion for example, or replaced if any tendon has broken.
a-3d show one form of energy dissipater D for use between adjacent wall panels as in
c and 3d schematically illustrate how the dissipater of
The dissipaters E in
Alternatively, the dissipaters D and E may be viscous dampers, or lead extrusion dampers for example.
a-e show five further forms of dissipaters for use between adjacent panels. The figures show left and right parts of two adjacent panels P, looking at the panels side on in each case. In each case the dissipater comprises a plate-like part 40a on one side and a similarly shaped right plate-like part 40b on the other side, which are fixed to the left and right panels P, for example by being screwed or bolted into the panel and/or through rebar anchors 41 glued into angled slots in the panel surface as shown. The dissipater of
a and 9b show one form of dissipater in more detail, for use at a joint between a beam B and column C. The dissipater comprises a rod or bar 10 of steel or other material which will yield to absorb energy during a loading event, which in the embodiment is shown necked down (reduced in diameter) in a central area (see
Typically all of the load bearing elements of the building will be engineered wood elements. However it is not intended to exclude that some of the load bearing elements may be formed of other materials. The connections may be between engineered wood columns and steel beams for example, or vice versa. In a preferred form all of the load bearing elements of the building are formed of engineered wood. In another form some of the load bearing elements are formed of engineered wood and some other elements are formed of solid wood or steel for example. The foundation F of the building will typically be a concrete pad. The building system of the invention enables the construction of lightweight low cost buildings, with energy dissipaters which may be replaced after extreme loading.
The building may be prefabricated before delivery to a construction site, by pre-forming the load bearing elements such as beams and/or columns and/or wall panels off site, to size. The components of the prefabricated building are delivered onsite, and the columns, beams, and/or panels put in place to form the frame of a single or multi-storey building, and the roof of the building is constructed. In such embodiments the invention provides a low cost modular prefabricated construction system forming pre-stressed non-concrete buildings, comprising protection against loading events such as earthquakes and extreme wind buffeting. The invention enables single and in particular multi-storey buildings to incorporating such protection, to be built in situations where cost may preclude the construction of a pre-stressed concrete structure.
The foregoing describes the invention including embodiments thereof. Alterations and modifications as would be obvious to those skilled in the art are intended to be incorporated in the scope hereof as defined in the accompanying claims.
Number | Date | Country | Kind |
---|---|---|---|
549029 | Aug 2006 | NZ | national |
This application is a continuation of U.S. application Ser. No. 12/376,687 filed Feb. 6, 2009, now abandoned, which was the National Stage of International Application No. PCT/NZ2007/000206, filed Aug. 7, 2007, the entireties of which are incorporated herein by reference.
Number | Name | Date | Kind |
---|---|---|---|
2837776 | Klein | Jun 1958 | A |
3226894 | Burchardt et al. | Jan 1966 | A |
3979863 | Hurley et al. | Sep 1976 | A |
4059931 | Mongan | Nov 1977 | A |
4249354 | Wynn | Feb 1981 | A |
4275537 | Pinson | Jun 1981 | A |
4875314 | Boilen | Oct 1989 | A |
4956947 | Middleton | Sep 1990 | A |
5123220 | Simenoff | Jun 1992 | A |
5168681 | Ayrapetyan | Dec 1992 | A |
5384993 | Phillips | Jan 1995 | A |
5386671 | Hu et al. | Feb 1995 | A |
5459973 | Baumann | Oct 1995 | A |
5531054 | Ramirez | Jul 1996 | A |
5535561 | Schuyler | Jul 1996 | A |
5657597 | Loftus | Aug 1997 | A |
5669189 | Logiadis et al. | Sep 1997 | A |
5675943 | Southworth | Oct 1997 | A |
6014843 | Crumley et al. | Jan 2000 | A |
6161339 | Cornett et al. | Dec 2000 | A |
6195949 | Schuyler | Mar 2001 | B1 |
6256943 | Mander et al. | Jul 2001 | B1 |
6282859 | Van Der Heijden | Sep 2001 | B1 |
6557316 | Van Der Heijden | May 2003 | B2 |
7150132 | Commins | Dec 2006 | B2 |
7313890 | Clarke | Jan 2008 | B2 |
Number | Date | Country |
---|---|---|
2002-364071 | Dec 2002 | JP |
U311286 | Jun 2005 | JP |
2005-282231 | Oct 2005 | JP |
2006-063771 | Mar 2006 | JP |
2006-083545 | Mar 2006 | JP |
Entry |
---|
Japanese Examination Report, JP Appln. No. 2009-523741, Jun. 25, 2012, pp. 1. |
Number | Date | Country | |
---|---|---|---|
20130019545 A1 | Jan 2013 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 12376687 | US | |
Child | 13471528 | US |