BACKGROUND
Current techniques for constructing larger buildings usually involve the use of a load bearing frame of steel or reinforced concrete, with attached cladding and/or masonry infills. In the case of masonry walls in such structures and elsewhere, it is necessary to provide additional strengthening where the area of the wall increases beyond certain limits. The strengthening is required to support the weight of the wall; to resist environmental loading such as wind forces, differences in air pressure and earthquakes; as well as to withstand other dynamic service loads such as crowd pressure, vehicle impact or explosions. The required strength for a given structure is governed not only by the laws of physics but also by local building regulations. In some cases it may also be necessary to divide the masonry infill wall into a number of smaller panels or sections separated by expansion joints so as to relieve such loads in the masonry, and/or to avoid excessive movement of the masonry in response to temperature variations, or cracking of the mortar or other jointing material e.g. due to differential shrinkage when drying or curing.
Traditionally where additional strength is needed, walls have been supported by cross walls, piers and areas of wall thickening. More recently the standard windpost has been developed, which occurs in most building walls (particularly interior walls), if their length exceeds 4 m. The purpose of the post is to stiffen or strengthen the walling, in circumstances of particular lateral stress from wind induced pressure differences, crowd or any other force. A wind post generally consists of a steel column secured at its top and base to the building frame or another suitable load-bearing structure. This form of construction, while effective, brings with it the following disadvantages:
1. An expansion joint is required on either side of the wind post, where it interfaces with the adjacent masonry. Filler material is inserted between post and block faces.
2. Frame ties typically at 225 mm centres must be provided between the masonry and the post on both sides.
3. Mastic will often be a specification requirement.
4. A steel post will require fire protection.
5. There may also be acoustic concerns.
7. The post typically requires four bolt fixings, two at the base and two at the soffit.
8. The post must be erected before the walling and so isolated access (e.g. scaffolding) is required for safe work practice particularly at height.
Our invention seeks to replace the windpost and also achieve many other positive characteristics in strengthening panels of bonded masonry such as masonry walls, both load bearing and non load bearing; and optionally easing the provision of expansion joints.
Our published patent specification WO2008/015407 discloses a method of constructing a masonry infill in a load bearing structure. The method involves laying one or more courses of masonry in an infill space in the structure and partitioning off a casting space having as its base the then uppermost course of masonry. The casting space extends from one side of the infill space to the other. Reinforcing material is then positioned in the casting space and an end of the reinforcing material is secured to the load bearing structure. The casting space is then filled with concrete and one or more further courses of masonry are laid on top of the filled casting space. The reinforced concrete forms a bond beam which strengthens the masonry. The reinforcing material may be rebar, secured to a load-bearing frame of the building by a body for reception of the rebar ends. The body allows longitudinal sliding movement of the rebar relative to the frame, but restrains relative lateral movement of the rebar. The resulting structure forms a cost effective alternative to a wind post reinforced masonry infill, produced using components that are easier to handle, and easier to install in confined spaces, as well as having other advantages.
Our published patent specification WO2009/098446 relates to a masonry infill in a load bearing structure which comprises hollow masonry units arranged to define a cavity extending through adjacent courses thereof, the cavity being filled with reinforced cementitious material e.g. reinforced concrete, a lower end of the reinforcement being secured to a load bearing support; a body being secured to the load bearing structure and receiving an upper end of the reinforcement so as to permit longitudinal sliding movement of the reinforcement upper end in the body, whilst constraining movement of the reinforcement in a direction transversely of the infill. The lower end of the reinforcement may be built into the support, or slidably received in a further body. Alternatively one or both ends of the reinforcement may terminate in a bond beam. Brackets may be embedded in the cementitious material in the cavity to transfer shear forces between the adjacent blockwork and the cementatious material. WO2009/098446 therefore discloses methods for providing generally vertically extending reinforced concrete structures in blockwork, e.g. as an alternative to or as a replacement for windposts, or as a reinforcement at the vertical edges of apertures in the blockwork, e.g. at the edges of window or door openings or service penetrations, or indeed at any other point in the blockwork as required.
Our published patent specification WO2009/147427 concerns a masonry wall reinforcing bracket comprising an elongate inter-course stress transfer member which comprises a rebar cradling feature. The stress transfer member may comprise a flat strip locatable within a perpend in a masonry wall. The bracket may further comprise a supporting member that protrudes perpendicularly from the length of the stress transfer member so as to be locatable within a bed joint of the masonry wall 10. The supporting member 28 may be a stabilising foot, so that the bracket is generally L-shaped. In this configuration the stabilising foot forms the shorter bottom limb of the L and the rebar cradling feature is a slot formed part-way along the stress transfer member, i.e. the longer vertical limb of the L. The slot has an open mouth at a side edge of the flat strip. The rebars and brackets are used in a bond beam system incorporated within the masonry wall. The brackets disclosed in WO2009/098446 may also be of this form. WO2009/147427 further describes connections between the end of a reinforced concrete column and the top or bottom side of a bond beam, and similar connections between the end of a vertical steel post and the top or bottom side of a bond beam.
The various components described in the foregoing patent specifications may be used in a wide variety of combinations and configurations so as to be capable of providing a similarly wide variety of reinforced masonry infills for pre-existing load bearing structures such as the load bearing frame of a large building. Where the pre-existing load bearing structure is made from steel columns and girders the body for reception of the rebar ends may be simply bolted to the load bearing structure. Where the pre-existing load bearing structure is of reinforced concrete, the body can be secured to it by expansion bolts, wall plugs and threaded fasteners, studs anchored in holes in the structure by epoxy resin, or any other suitable fastening technique.
Although not previously considered for this purpose, such a body for reception of rebar ends could be used to terminate a bond beam within masonry (e.g. blockwork) at the side of a reinforced concrete column, slab or other volume of reinforced concrete also encased within the masonry (e.g. a column formed in accordance with WO2009/098446). Moreover an expansion joint could be provided between the masonry encased column or the like and an adjacent panel of masonry (e.g. blockwork) containing the bond beam, e.g. to accommodate thermal movement of the panel and mitigate cracking due to mortar shrinkage on curing. Expansion joints may also be useful in accommodating other deflections of the building under load, e.g. building settlement, and deflections arising under the above described environmental and service loads. However, improvements in, or additional options for, fixing the body to the masonry shell around the reinforced concrete column or the like are desirable.
SUMMARY OF THE INVENTION
The present invention therefore provides a body securable adjacent an exterior surface of a masonry skin or shell, the body being adapted to receive the end of an elongate reinforcement for reinforcing a cementitious material, and a mounting arrangement adjustably securable to the body and engageable with a further elongate reinforcement positioned for reinforcing cementitious material behind the masonry skin or shell therein, so that the body is secured to the further elongate reinforcement. As the body is not only mounted to the masonry skin or shell but is also engages (e.g. is directly secured to) the further elongate reinforcement and cementitious material behind the masonry skin or shell, this reinforced cementitious material as well as the masonry can act to resist the lateral loads from the end of the elongate reinforcement received in the body. Preferably the body is adapted to receive the end of the elongate reinforcement so that when encased in the cementatious material longitudinal movement of the elongate reinforcement relative to the body is allowed but transverse movement of the elongate reinforcement relative to the body is restrained.
The mounting arrangement may comprise a hook or eye by which it is securable to the further elongate reinforcement. Alternatively the mounting arrangement may comprise a strip or plate having a slot in which the further elongate reinforcement is received for securing the mounting arrangement to it. Preferably however the mounting arrangement comprises a sleeve through which the further elongate reinforcement passes for securing the mounting arrangement to it.
More than one such body may share a single such mounting arrangement. The mounting arrangement (whether for one or more bodies) may be securable to more than one such further elongate reinforcement positioned behind the masonry skin or shell.
The mounting arrangement may comprise a threaded fastening by which it is secured to the body. This may allow adjustment of the distance between the body and the further elongate reinforcement, so that the body can be held closely adjacent to the exterior surface of the masonry skin or shell when secured to the further elongate reinforcement. The threaded fastening may comprise a bolt received in a threaded hole. Preferably however the threaded fastening comprises a threaded bar or stud received in a threaded hole or nut provided on a sleeve through which the further elongate reinforcement passes for securing the mounting arrangement to it. One end of the threaded bar or stud passes into the interior of the sleeve so as to be clampable against the further elongate reinforcement. The other end of the threaded bar or stud carries a nut for securing it to the body.
The body may comprise a cleat having a mounting flange with a hole through which the threaded fastening passes. Two or more such holes may be provided. The cleat may further comprise one or more sockets for slidable reception of the elongate reinforcement ends. Alternatively, the cleat may comprise one or more spigots each for reception within a socket secured (e.g. welded) to the end of the elongate reinforcement. The head and/or foot of a column, panel or other volume of cementatious material containing the further elongate reinforcement(s) may be secured to adjacent load bearing structures (e.g. a foundation and soffit, beams or floor slabs) by similar spigoted cleats arranged to cooperate with socket(s) secured to the ends of the further elongate reinforcement(s). Additionally or lternatively some or all of the ends of the further elongate reinforcements may be received in sockets provided on one or more of the corresponding cleats.
The invention therefore may be used to provide a masonry clad volume of reinforced cementitious material, a panel of masonry and an expansion joint between the masonry clad reinforced cementitious material volume and the masonry panel, in which the masonry panel contains a bond beam and in which an elongate reinforcement in the bond beam has an end coupled to a further elongate reinforcement in the volume of cementitious material by a body and mounting arrangement as described above.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention and various preferred features and advantages of it are further described below with reference to illustrative embodiments shown in the drawings, in which:
FIG. 1 shows a hook type mounting arrangement for use in embodiments of the invention;
FIG. 2 shows an eye type mounting arrangement for use in embodiments of the invention;
FIG. 3 shows a mounting arrangement with a slotted plate, for use in embodiments of the invention;
FIG. 4 shows a mounting arrangement comprising a sleeve, bolt and threaded hole, for use in embodiments of the invention;
FIG. 5 is a plan view of an elongate reinforcement receiving body in the form of a cleat, for use in embodiments of the present invention;
FIG. 6 is a side view corresponding to FIG. 5;
FIG. 7 is a side view of a mounting arrangement comprising a sleeve and studs, for use in embodiments of the invention;
FIG. 8 is an end view corresponding to FIG. 7;
FIG. 9 shows the cleat of FIGS. 5 and 6 assembled together with the mounting arrangement of FIGS. 7 and 8, and a hollow block and rebars;
FIG. 10 shows part of a hollow blockwork encased, reinforced concrete column and an adjacent blockwork panel incorporating a bond beam, the panel and column being separated by an expansion joint and one block being omitted so as to show a cleat and mounting arrangement assembly corresponding to that of FIG. 9;
FIG. 11 shows an alternative sleeve and stud mounting arrangement to that of FIGS. 7 and 8;
FIG. 12 shows a cleat with spigots, which may be used in embodiments of the invention;
FIG. 13 shows a terminal rebar with a socketed end;
FIG. 14 shows two such socket ended rebars assembled together with the spigoted cleat of FIG. 12;
FIG. 15 shows a stage in the construction of a stack bonded hollow block encased reinforced concrete column;
FIG. 16 shows a further stage in this construction process;
FIG. 17 shows a header detail of a column, panel and expansion joint corresponding to those of FIG. 10, with another block omitted to show internal reinforcement details, and
FIG. 18 shows another form of hollow block.
DETAILED DESCRIPTION
FIG. 1 shows a mounting arrangement 10a for the elongate reinforcement end receiving body. This mounting arrangement has a hooked end 12 which can embrace the circumference of a further elongate reinforcement (e.g. a steel rebar, not shown) positioned behind a masonry skin or shell, such as inside a hollow blockwork casing so as to form a blockwork encased reinforced cementitious material column, (e.g. a reinforced concrete column). The masonry may be of any suitable kind, such as brick, cement blocks or natural or artificial stone. The further reinforcement may be received in any suitable volume of cementitious material behind the masonry skin. The mounting arrangement 10a also has a threaded shank 14 forming a threaded fastening which can be passed through a hole formed through the side of the encasing hollow block or other masonry skin, shell or cladding, so as to be secured to the elongate reinforcement receiving body externally of the masonry. For this purpose, the elongate reinforcement receiving body may be provided with a through hole through which the end of the shank 14 is passed. A nut can then be screwed onto the shank end, to secure the body adjacent to an outer surface of the masonry, but also anchoring it to the further elongate reinforcement (rebar) and surrounding concrete behind the skin or shell (e.g. inside a hollow masonry block).
As a preferred option, the body may take the form of a cleat such as 30a shown in FIGS. 5 and 6, in which ends of elongate reinforcing members external to the column or other volume of reinforced cementitious material (e.g. ends of steel rebars in a bond beam formed in an adjacent masonry panel) are received in sockets formed by tubular pockets 36. The pockets permit longitudinal sliding movement of the rebars, but restrain them against lateral movement. The cleat further comprises a base plate 32 with through holes 34 through which the free end of the shank 14 can pass and then be secured by a washer and a nut screwed down the protruding tip of the shank 14 against the outer face of the base plate 32.
Two (as shown) or more such holes 34 may be provided, each receiving a respective mounting arrangement 10a in a respective hole through the masonry skin or shell, with the hooked ends 12a engaging the same or a different internal (i.e. further) elongate reinforcement. The holes 34 are elongated, so as to permit adjustment of the cleat position longitudinally of its base plate. This adjustment may accommodate thermal movement of the masonry panel in the vertical direction. For this purpose, the securing nuts may be left fairly loose, e.g. finger tight, and locked by backing nuts also received on the protruding tip of the shank 14.
The mounting arrangement 10b of FIG. 2 is similar to the mounting arrangement 10a, except that it has a closed loop or eye 12b in place of the hooked end 12a. The loop may be closed by welding. It is passed over the top of the column etc. internal elongate reinforcement or rebar and slid down close to its desired final position. The shank 14 is passed trough a pre-drilled hole in the associated masonry unit as it is being laid. The cleat 30a or other external elongate reinforcement end receiving body is then secured to the protruding shank tip as described above.
As shown in FIG. 3, the mounting arrangement is similar to that of FIG. 1, but the hooked end 12a is replaced by a slotted metal plate or strip 12c. This is welded to the shank 14. The slot is L-shaped, with an open mouth at one of the long side edges of the strip 12c. The cross-section of the internal elongate reinforcement is received in the slot and the mounting arrangement 10c otherwise operates in the same way as those of FIGS. 1 and 2.
FIG. 4 shows a further form 10d of the mounting arrangement. This comprises a circular sectioned tubular sleeve 16a which is threaded over the upper end of the internal elongate reinforcement e.g. rebar. A housing 20a with a radially directed threaded hole is welded to one side of the sleeve 16a. A threaded fastener in the form of a bolt 18a is inserted through the hole 34 in the cleat base plate 32 and through the hole pre-drilled in the masonry skin, shell or cladding. It is then screwed into the housing 20a hole to secure the cleat to the internal rebar and to the surrounding reinforced cemetitious material, once this has been cast behind the skin or shell, e.g. in a columnar space formed inside a stack of hollow masonry blocks. The sleeve 16a may have a pair of the housings 20a spaced along its length at a separation corresponding to that of the holes 34 in the cleat base plate. Each housing may therefore accept a respective bolt 18a passing through each base plate hole 34. A single mounting arrangement 10d comprising a single sleeve 16a and a pair of bolts 18a can therefore be used to secure the cleat to an external surface of the masonry skin or shell.
The mounting arrangement 10e shown in FIGS. 7 and 8 comprises a pair of nuts 20b welded over circumferentially aligned side holes at either end of a tubular sleeve 16b. A threaded fastening in the form of a stud 18b is screwed into each nut 18b so that the tips of the studs enter the bore of the sleeve 16b. The other (outer) ends of the studs 18b have cross-slots 46 engageable by a flat bladed screwdriver so that the studs can be screwed into the sleeve 10e until their inner ends tightly engage and clamp a rebar or other elongate reinforcement received in the sleeve 16b. Of course, any other suitable rotational drive arrangement could also be used. The sleeve 16b without the studs fitted can therefore be slipped over the upper end of an internal (further) elongate reinforcement and slid downwards to approximately the desired location. The studs can be inserted through pre-drilled holes in the encasing hollow block or other masonry shell/skin, and threaded into the nuts 20b. Tightening the studs with a screwdriver or other suitable tool will lock the sleeve 10e and studs 18b to the internal elongate reinforcement at the correct location. Protruding outer ends of the studs 18b can be inserted through the cleat base plate holes 34 to secure the cleat in position against an outer face of the encasing block etc. using washers, nuts and backing nuts as required, again allowing for compensatory movement of the cleat in the vertical direction if desired.
FIG. 9 shows the mounting arrangement 10e and cleat 30a thus secured respectively within and upon a hollow encasing block 60. The studs pass through holes 62 pre-drilled into a header face of the block 60. An internal rebar 38a is received and secured in the mounting arrangement sleeve 16b and further rebar ends 40a, 40b are slidingly received in the two cleat pockets. The cleat base plate is secured to the studs by nuts 42 and washers 44, in a manner permitting limited longitudinal sliding, if required. Backing nuts (not shown) or any other suitable locking means may be used to retain the nuts 42 in the correct position.
FIG. 10 shows the mounting arrangement 10e and cleat 30a in position in a reinforced concrete column 64 encased by hollow blockwork and in an adjacent blockwork panel 66 respectively. An expansion joint 70 separates the column 64 from the panel 66. The expansion joint is formed in any suitable manner as may be used in standard blockwork walls, for example a strip of Corofil™ packing whose otherwise exposed edges are covered and sealed by a bead of mastic. The base of the cleat 30a lies in the plane of the expansion joint 70. The column contains a pair of elongate reinforcements 38a, 38b, e.g. steel rebars. One of these (38a as shown) passes through the sleeve of the mounting arrangement. The panel 66 has a bond beam formed in it, encased within a course of blocks 68 having a U-shaped cross-section. The rebars 40a, 40b serve to reinforce the bond beam. The rebar ends and cleat pockets are covered by heat shrinkable boots 72 so as to maintain the longitudinal slidability of the rebar ends even when they and the cleat pockets have been encased in the concrete of the bond beam. The bond beam may comprise stress transfer brackets for transmitting stresses between the bond beam and adjacent courses of the masonry panel and for cradling and supporting the rebars 40a, 40b during casting of the bond beam, as described in WO2009/147427. A half block of the column 64 and an adjacent half block at the end of the bond beam and their respective concrete fillings are omitted in FIG. 10 so that the mounting arrangement 10e and cleat 30a are exposed and visible. Normally these components and their associated rebars will be fully concealed within the encasing blockwork and its concrete filling. Externally, the reinforced blockwork is therefore indistinguishable from standard, solid masonry, which can have aesthetic advantages. Where conditions dictate (e.g. for taller panels or panels having openings in them at various heights) the panel may be reinforced by several such bond beams.
The encasing masonry and the surrounding concrete or other cementitious material provides the internal metal reinforcements (e.g. rebars, cleats, cleat mounting arrangements, stress transfer brackets) with adequate corrosion and fire protection in many instances. The airtightness, thermal and acoustic performance of the column 64, expansion joint 70 and adjacent reinforced masonry panel 66 is similar to that of a plain panel of solid masonry blocks. The masonry of the panel 66 above and below the bond beam can comprise lightweight blocks e.g. of foamed cconcrete where these will provide adequate strength, thereby reducing the weight on the load bearing structure and increasing the thermal performance of the building. All of the components used to form the reinforced masonry infills resulting from the present invention, as shown for example in FIG. 10, are relatively small and light, and can meet the statutory requirements for manual handling. No lifting or other load handling equipment is therefore necessary in the construction process. The construction methods can also be used in sites having restricted access.
The mounting arrangement 10f shown in FIG. 11 is a further development of that 10e shown in FIGS. 7 and 8. It comprises a pair of sleeves 16c connected together in parallel by two lengths of rebar each welded at either end to sides of the sleeves so as to form a generally rectangular frame. The sleeves are each provided with welded-on nuts 20c overlying through holes, similar to the nuts 20b and through holes shown in FIGS. 7 and 8. These may be distributed circumferentially about the ends of the sleeves, proximate the connecting rebar 74 ends as shown. Studs 18b may be selectively screwed into the nuts 20c so as to secure one or more rebar (or other elongate reinforcement) end receiving bodies (e.g. cleats 30a as shown in FIGS. 5 and 6) to the mounting arrangement 10f in a number of different possible configurations. For example the generally planar configuration of four studs in two pairs, each pair extending oppositely away from the connecting rebars 74, may be used to link a further panel of bond beam-containing masonry to the column 64, opposite the bond beam containing panel 66; i.e. adjacent to the left hand vertical edge of the column 64 shown as a free edge or reveal in FIG. 10. In this configuration, the mounting arrangement 10f would be used in place of the mounting arrangement 10e to secure two opposed cleats 30a with their bases at opposed expansion joints 70. The rebars 38a and 38b internal to the column 64 would be received in respective ones of the sleeves 16c. In this way a straight length of masonry wall containing the column 64 somewhere in the middle, and a pair of expansion joints, one on either side of the column, will result.
Additionally or alternatively, the nuts 20c at right angles to the connecting rebars 74 can receive cleat mounting studs 18b, so as to link further bond beam containing masonry panels to the column 64 at right angles to the panel 66 of FIG. 10. Again the further cleats or rebar end receiving bodies so mounted may have a base plate in the plane of an expansion joint formed with the outer surface of the hollow masonry encased, reinforced cementitious material column or other volume. The welded-on nuts 20c may be distributed at other angles around the circumference of the tubes for use in linking bond beam containing masonry panels to the column etc. at any desired angle, besides at 0°, 180° and 90° as already described. The mounting arrangement sleeves 16a and 16b of FIGS. 4, 7 and 8 may be similarly provided with further housings 20a and nuts 20b distributed at any suitable angles about their circumferences.
The column shown in FIGS. 10 and 17 uses half blocks to form every other course of the hollow encasing masonry, and a half block in the corresponding courses of the adjacent masonry panel 66. In this way, the “stretcher bond” pointing pattern of the panel is continued into the column, apart from the interruption necessarily occurring at the expansion joint 70. FIGS. 12-16 show stages in the construction of a stack bonded, hollow masonry encased, reinforced cementitious material column. Such a column can be used in place of the columns 64 of FIGS. 10 and 17. Equally the construction process of FIGS. 12-16 can be readily adapted to produce columns as shown in FIGS. 10 and 17, simply by using hollow half blocks in the appropriate alternate courses.
FIG. 12 shows a rebar (or other elongate reinforcement) end securing cleat 30b comprising a base plate 32a having elongate securing holes 34a similar to the holes 34 of cleat 30a (FIGS. 5 and 6). Cleat 30b further comprises a pair of upstanding spigots 36a formed by circular section metal rods welded to the base. The spigots are dimensioned to form a snug sliding fit within a tubular socket 80 welded to the end of a terminal rebar 82 (FIG. 13). The cleat can be fixed to a foundation, floor slab, beam or the like of a pre-existing load bearing structure in a position at the base of where it is desired to erect the column (or other volume of reinforced cementitious material). Bolts, expansion bolts or other appropriate fasteners are used for this, passing through the base plate holes 34a. A pair of terminal rebars 82 is then fitted to the cleat 30b by engaging the sockets 80 over the spigots 36a (FIG. 14). To form a column, a bed of mortar or like jointing material is spread around the base 34a of the cleat 30b. A hollow block 84 is then laid in the mortar in the correct position to form the first course of encasing masonry for the column. The upper rim of the block 84 just laid is spread with a layer of mortar and the next block 86 is laid in stack bond on top of it (FIG. 15). Further blocks are laid similarly in succession until only just sufficient length of each terminal rebar 82 protrudes above the top block to form a lap joint with a length of plain rebar (or other elongate reinforcement) which is to be joined to the projecting upper end. Once the lap joints have been secured e.g. by wire ties or the like, further hollow blocks can be laid in stack bond, threaded over the tops of the plain rebars 38c, 38d (FIG. 16). Further lengths of plain rebar (or other elongate reinforcement) can be secured by lap joining until the desired height for the column is reached. The cavity enclosed by the stacked hollow blocks can be filled with concrete or other cementitious material at suitable intervals as block laying progresses. The depth of fill should not be so great as to make tamping/vibratory compaction difficult; neither must the interval between successive pours be too great so that excessive curing takes place, leading to a risk of “cold joints” and weakness in the final cast column filling.
The adjacent masonry panel (such as 66 in FIGS. 10 and 17, but not shown in FIGS. 15 and 16) may be built up course by course simultaneously with the column blockwork, or afterwards. Expansion joint packing material is built in as the work progresses. When the column reaches the height of a bond beam course in the adjacent masonry panel, a hollow block 60 is laid having pre-drilled holes (not visible in FIG. 16) through its header face at the expansion joint plane. The sleeve 16b of a mounting arrangement 10e (for example, as other mounting arrangements can also be used as appropriate) is threaded over the upper end of the rebar 38d and slid into position with its nuts 20b aligned with the pre-drilled holes. The pair of studs 18b are then inserted through the holes and nuts and are screwed tight against the rebar 38d to clamp the mounting arrangement securely in position. A cleat 30a or other suitable rebar end receiving body may then be secured to the protruding ends of the studs 18b as described above. Once the ends of the bond beam rebars have been inserted in the cleat pockets, the resulting assembly will be the same or similar to that shown in FIG. 9. Further courses of the column encasing blockwork may then be added and filled in the same way.
FIG. 17 shows a head or soffit termination for a hollow masonry encased, reinforced cementitious material column. Prior to laying the final courses of the column, terminal rebars 82 are lap joined to the rebars 38a, 38b or 38c, 38d, with their sockets engaged over the depending spigots of a cleat 30b secured to a pre-existing, overhead load bearing structure such a steel joist section 88. Further blockwork courses are then laid and filled until the column reaches the full height of the soffit. An expansion joint packing e.g. also of Corofil may be included between the final blockwork course and the steel joist. The terminal rebars are preferably not pushed fully home onto the cleat 30b spigots, but a gap 90 of at least the thickness of the expansion joint packing and preferably about 30 mm is left between the upper end of the terminal rebar sockets and the cleat base plate. This allows for thermal and other movement between the top of the column and the overhead load bearing structure. To enable the final blockwork courses to be threaded over the terminal rebars as they are laid, centre sections in the headers of the hollow blocks may be cut through vertically, so that the blocks have a C-shaped horizontal cross-section. The concrete or other cementitious filling for the final course can be trowelled in through the expansion joint gap, or pumped in/injected. Head portions of other reinforced, masonry faced, cementitious material volumes may be terminated and secured to an overlying load bearing structure in a similar manner.
The spigoted cleat 30b and the socketed cleat 30a described above may be substituted one for the other, for co-operation with socketed or plain rebar (or other elongate reinforcement) ends as appropriate.
It is also possible to omit the expansion joints 70 from the structures shown in FIGS. 10 and 17. In that case the two half blocks on either side of the junction between the column 64 and the panel 66 on every other course are replaced by a single whole block as shown in FIG. 18. Such blocks have a central vertical partition 92 running in the thickness direction and connecting the front and rear walls of the hollow block. This partition serves to retain the wet cementitious filling in the column. Alternatively, hollow blocks as shown in FIGS. 15 and 16 could be used, with the halves of their base apertures which extend into the panel 66 being closed off by a sheet of cardboard or the like incorporated in the bed joints during construction.
Patent Application
20130333318
