AU2001263323A1 - Construction of high-rise building with large modular units - Google Patents

Description

CONSTRUCTION OF HIGH-RISE BUILDING WITH LARGE MODULAR

UNITS

Related Applications The present application claims the benefit of the filing date of provisional application Serial Number 60/205,254, filed on May 19, 2000.

Background of the Invention

The present invention relates to the construction of buildings using modular components, and more specifically relates to the construction of high rise buildings using pre-cast modular components formed at ground level.

Description of Related Art The construction of high rise buildings using conventional methods is an expensive and risky process, because as successive floors are built, the work must be performed at greater heights. Forming walls, floors and ceilings is difficult, because workers have to operate in a dangerous environment, and the scaffolding and forms used in the construction have to be lifted and positioned high above the ground as well as assembled and disassembled on each floor.

Finishing work to install utilities, doors and windows, and quality checking also have to be performed at a great height, resulting in increased risk to workers and in a reduced quality of the work, compared to work performed on the ground. The large amount of work done at great heights thus results in higher costs for manpower, insurance and equipment, as well as in a reduction of the quality of the construction. Partially because of the difficulty in working at heights, reinforcement of the building against natural forces such as earthquakes and hurricanes is difficult.

Summary of the invention The present invention is directed to a method of construction of high rise buildings that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. Additional features of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention.

The new method of building high-rise precast repeating unit structures according to the invention is especially well suited to the construction of buildings such as apartment buildings, hospitals and hotels, which have essentially identical floor plans at every level. The method according to the invention uses precision-formed precast modular components, similar to those used for single family residences and low rise apartment buildings, and combines them to form floors of high rise structures able to significantly improve the finished building's ability to withstand maximum intensity hurricane and seismic lateral forces. According to the method of the present invention, the precast modular components are formed at ground level, and lifted in position by a self climbing tower gantry crane, and then are secured to the already formed structure with concrete pours. This technique contributes to several advantages over conventional methods of construction. Greater safety during construction is achieved, since most of the work is done at ground level. The quality of construction is improved, since the building can be finished with greater precision. Similarly, the finished building is stronger, thus safer once occupied. In addition, the system according to the invention results in time and cost savings, since large portions of the work are done on the ground, and the mechanized casting of the modules is substantially faster than conventional methods of construction.

To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described, the invention is a method of constructing a high-rise building, comprising forming at ground level precast modules defining portions of a level of the building, lifting the precast modules in position on the level of the building, pouring a concrete overlay diaphragm on a floor of the level, such that the precast modules are held together in position, and pouring concrete in spaces between vertical walls of the precast modules.

In another aspect, the invention is a method of construction for a modular level of a high-rise building, the level having a floor, comprising placing a precast module on the floor, such that the precast module defines a portion of the level of the building, placing additional precast modules on the floor to define additional portions of the level, leaving spaces between adjoining vertical walls of the precast module and of additional modules that are mutually adjacent, pouring a concrete overlay diaphragm on the floor, such that the concrete flows through passages in the vertical walls of the module and additional modules, and pouring concrete in the spaces between adjoining vertical walls.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Brief Description of the Drawings

The accompanying drawings are included to provide a further understanding of the invention, are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the objects, advantages, and principles of the invention. In the drawings,

Figurel is a perspective elevation view showing a 40 story building constructed according to one embodiment of the invention;

Figure 2 is a floor plan view showing an exemplary floor layout of the building of Figurel , and precision casting forms according to the invention;

Figure 3 is an isometric view showing a diagram of an initial construction stage of the building according to the invention; Figure 4 is an isometric view showing a diagram of a next construction stage of the building according to the invention;

Figure 5 is an isometric view showing a diagram of a detail of a wing;

Figure 6 is a diagram showing placement of a precast module;

Figure 7 is a floor plan detail showing the connection of several precast modules; and

Figure 8 is a diagram showing one embodiment of the interference fittings of the precast modules.

Detailed Description of the Embodiments The present invention utilizes precast units formed at ground level to construct high-rise buildings, many stories in height. In order to illustrate this process clearly, the steps for construction of an exemplary 40-story building according to the system of the invention are described with reference to the drawings. The exemplary 40-story structure shown in completed form in Figure

1 can include a general purpose Ground Floor 2, thirty-nine residential floors or levels constructed above it, and a half-floor 4 for the forty-first level occupied by elevator equipment rooms and several large cisterns for fire and plumbing services. Each floor has a central core 6 with six elevators, stairs and multiple facilities, and four residential wings 8. Each wing is occupied by four apartments of one-to-three-bedrooms. The building of this example has a total of 624 apartment units.

Although the exemplary building has four wings and a central core area, the system according to the invention can be used to construct buildings with more or fewer wings. The central core also is not a necessary component of the design. The principal requirement for use of the system is that each floor can be formed by combining essentially identical elements that are formed at ground level. Consequently, the number of apartments, layout of the apartments, number of elevators and other architectural details can vary while remaining within the scope of the invention. The system will be described below in its successive steps.

Step 1. site preparation.

Construction of the building begins with site preparation. The site can be prepared by utility and foundation sub-contractors, and includes, for example, building the foundations of the building. The foundations typically consist of a thick mat foundation, which may require support by piles or drilled shafts in weaker soils. Underground utilities connections will also typically be put in place in this step. Foundations for both the wings 8 and the core section 6, if present, are formed at this stage.

Step 2, precision-forms set up.

The next step according to this exemplary embodiment of the invention consists of setting up the precision forms used to make the precast modules. Four large concrete working slabs 10 are cast and finished between the wings of the building, as shown in Figure 2. When the working slabs 10 are cured, eight precast concrete precision forms, for example two each of precision forms A, B, C and D, are assembled upon these large concrete slabs 10. The four largest (and heaviest) modules, two A's and two B's, are placed closest to the core area 6, in order to reduce the required lifting capacity of a centrally located self climbing tower gantry crane. The size and number of the precision forms depends on the size of the precast modules that are required for assembly of each floor of the building. The precision forms, in a preferred embodiment, can have a closed position to hold the concrete in the desired shape until it is cured, and an open position to facilitate removal of the finished pre-cast module from the precision forms and either staged or direct placement of the module into the building structure.

Step 3. casting concrete for first and second floor core and wings. Casting concrete for the first and second floor core section 6 and for the four wings 8 takes place next. Work in this phase is commenced by setting up, bolting and bracing a 104 tonnes self climbing tower gantry crane 20 at the center of the first floor core area slab. The tower self climbing gantry crane can be rated, for example, for up to 52 tonnes at 27.4m. The structures forming the first floor (ground level) and extending vertically to the second floor slab are built conventionally, because this level is typically taller and differs in lay-out from the upper 39 residential floors above. The ground level typically includes a large foyer and lobby, large utility rooms, and other structures that do not recur in the other floors. In this step, vertical shear walls 22 are erected and braced for both wings 8 and core 6 with cast concrete, as shown in Figure 3.

As soon an the vertical shear walls 22 and support columns 24 of the core section are cured, the required number of flying-form tables 26 are assembled between these structural elements, to facilitate casting of the second floor slab 27 for the core section 6, as shown in Figure 4. Floor slabs 30 for the remainder of the wings 8 of the second floor are also poured, to provide a support for the following levels.

Immediately following the casting of the second floor slab 27, the second-to- third floor core shear walls 28 are prepared, and cast as soon as practicable. The elevator lobby slab is blocked out from this pour where the tower gantry crane is located, to be closed at a later date through a secondary pour. According to a preferred embodiment of the invention, the entire core section 6, when it is present, can thus be built in a conventional manner using a variety of conventional techniques or methods. Because the core section contains vertical openings for stairs and elevator shafts, it is not ideally suited to be built with the modular precast modules of the invention. However, the core 6 could also be built using precast modules. In general, construction of the core section 6 should be about two or three floors ahead of the level where the precast modules are being placed. Any suitable method of construction can be used to build core section 6. For example, if flying_.forms 26 are used, a three day cycle time for construction of the floors of core section 6 can be expected. This cycle time of the core becomes the limiting factor that determines how fast the building can be constructed.

Once the second floor core slab 27 is poured, the flying-form tables 26 are moved on top of the second floor core slab 27, to prepare to cast the third floor. The third floor core slab concrete, not shown in the drawings, is cast using flying-form tables 26 in a similar manner as the second floor core slab 27. Since the flying-form tables 26 are attached to the vertical support columns 24 and/or to the shear walls, and not to the preceding floor, it is not necessary to wait for a floor slab to cure before pouring the successive floor. In a preferred embodiment, the flying-form tables 26 can be mounted on extendable jacks attached to the columns 24 and/or to the shear walls, to facilitate removal once the floor slab is poured.

While forming of the floor slabs with the flying-form tables 26 is taking place, the precision forms to build the precast modules 31 can be prepared at the ground level. Once precision forms A, B, C, and D are ready, preparation and casting of the first eight precast precision-formed modules 31 can begin. In different embodiments according to the invention, a number of precast modules different than eight can be formed, as required by the building plan. Step 4. cycle of preparation and casting of the first set of precast precision-formed modules.

The eight precision forms will each produce a module 31 daily. Each module 31 can be of a different type (for example, two of each made from precision forms A, B, C and D), and have a dedicated crew that performs the following tasks, preferably from early morning to mid-afternoon. The tasks are designed to prepare the precision forms for forming the precast modules 31 , and once the forms are ready, the precast modules 31 are constructed. The tasks include: a) Cleaning, lubricating and applying form-release oil to precision form surfaces and parts, performing maintenance on the precision forms; b) Securing gunwale block outs, waffle panels and/or stud strips to the forms, to facilitate flow of concrete, as will be described later; c) Securing door and window frames to the exterior wall of the form's core, providing the door frames with a lower steel closure strut or poured crosspiece 51 to provide torsional rigidity for the module, as shown in Figure 6; d) Placing and securing wire mesh and reinforcing steel into the forms in the opening between the inner core an the outside roll back form jacket; e) Securing electric wiring, distribution boxes and other inclusions; f) Inspecting and approving or rectifying the assembly of components in the precision forms before closure; g) Closing and casting the forms with, for example, between about fc' = 4000 psi and fc' = 6000 psi concrete; h) Applying vibration and finishes to help flowing the concrete; i) Curing the concrete to attain a release strength of, for example, about fc' = 2800 psi by the following day; j) Opening the forms, cleaning, rubbing and spraying the forms with curing compounds; k) Completing, sealing and testing the windows; I) Inspecting and releasing, if approved, each precast module 31 ; m) Lifting the precast modules 31 by the tower crane 20 to the active Floor level.

The tasks performed as described above are exemplary. The specific order and the necessity of the various tasks can vary depending on the specific requirements of the building being built. The precast modules can have five surfaces, as shown in the example of Figure 4, such as four sides 33 and a roof 64.

Since most of the preparation and inspection work for the precast modules 31 is carried out at the ground level, the workers operate in a much safer environment, and can work more efficiently while obtaining a superior final product. Inspection of the work done is also easier, and can be more thorough, resulting in improved quality of the building. Equally important, the construction proceeds faster and at less cost than otherwise possible.

Step 5, placing in position of modules C and D on the second floor slab. The first modules lifted in place by the gantry crane 20 are two C and two D modules, placed in position as shown in Figure 5. These modules occupy the extreme ends of the wings. Construction laser survey points 35 are used to control the precise placement of precast modules 31 by the tower gantry crane 20. The precise positioning and number of survey points 35 can vary depending on the specific plan of the building. In addition, major construction control points 36 can be established at each of the external building corners, shown in Figure 5.

At the major construction control points 36, each precast module can be provided with a special stiffening column 38. The purpose of these columns 38 is to prevent tension from forming along these most external points of the structure during extreme wind loading. Each column 38 can have an embedded hollow duct 40, and within it, a high strength steel dowel 42. For example, dowel 42 can be a threaded 1.25" diameter hardened steel rod. As each precast module 31 is slowly lowered into place, the dowel 42 is connected to the corresponding aligned dowel emerging from the floor slab of the prior lower level, for example through a mechanical threaded sleeve.

An alternative or additional tie can be obtained with post-tensioning steel tendons. In the case of construction of the second floor, the dead-end anchorage is secured in the ground floor slab at post-tensioning dead anchor points 44, similar to those shown in Figure 6. The steel tendons provide a vertical tension that ties together the floors at the outer corners. Jacking takes place at each new floor as the building progresses.

For applications where building codes or natural conditions are not as demanding, the columns 38 and the steel tendons may be omitted. The columns and the steel tendons, either together or separately, provide the finished building with additional strength to resist lateral loads imparted by earthquakes, hurricanes, and other phenomena.

Each of the modules C and D are designed with openings 50 formed along the bottom of their shear walls 33, as shown in Figure 6. These openings 50 are also referred to as "gunwales", because they are similar to those employed by ships to drain the water from the deck. The purpose of these gunwales 50 is to provide a free flow of concrete between and among all the modules of each floor through the shear walls 33. For example, once all the precast modules forming a floor of a wing 8 are put in place, a concrete overlay diaphragm can be poured on that floor, to cement together the precast modules with a common floor. The gunwales 50 permit free flow of the concrete between all the modules of wing 8. In most cases this will be a single pour, designed to couple and join all wings and the core together, rather than a pour covering only one wing. Also, the gunwale size and locations will be determined by specific building design.

Another special feature used in each of the modules C and D is the use of wall and floor waffles 53, as shown in Figure 8. These indented surfaces, or waffles 53 are provided to lock the shear walls 33 of all the modules of each floor with the slab overlay 30. The waffle effect can be achieved on the shear walls 33 by forming vertical ribs or vertical and horizontal grids on the outer jacket of the precision form. The flow of stress between these diverse elements is enhanced by these mechanical interlocks.

An alternative interlock mechanism is shown in Figure 6. Stud strips 52 are provided on each module 31 along the inner walls 33 and roof panel of the module. These stud strips 52 serve to mechanically tie each successive module to the rest of the structure already put in place. Stud strips 52 are secured, for example, in floor slabs 30, formed with the prior lower level, so that a stronger connection of the precast module with the floor slabs 30 can be made after the concrete overlay is poured. Their function is the same as that of the waffle surfaces described above.

Other types of known interference fittings, in addition to wall and floor waffles 53 and stud strips 52, can be used to strengthen the connection between shear walls 33 and floor slab 30.

Step 6, placing in position modules A and B on the second floor slab.

Once the precast modules C and D are in place, precast modules A and B are lifted and put in place in a procedure similar to the one described above. The precast modules A and B, like modules C and D, are readied on a rolling basis as production with the precision forms takes place. Modules A and B can be positioned in-board from the C and D modules, as shown in Figures 5 and 7. The precast modules A and B will abut the core area 6 through a commonly shared shear-wall 60. The modules A and B forming the second floor are put in place only after the flying-form tables 26 used to construct core 6 have been removed from the second floor slab, and are moved to the next upper level in preparation of casting of the third floor slab. Step 7, placing in position a second set of eight modules.

The same process is carried out for all the wings 8 of the building. The precast modules A, B, C and D are formed as necessary, and are moved in place on the second floor slab 30 as they are readied. For each wing 8, modules C and D are placed first, followed by modules A and B.

When the precast modules A, B, C and D are placed in position on the second floor slab 30, spaces 62 shown in Figure 7 are left open between the precast vertical shear walls 33 of the modules. These spaces 62 will be filled in a subsequent step described below, to increase the strength of the structure.

Step 8, casting a concrete overlay diaphragm for the second floor slab.

Once all precast modules A, B, C and D are placed in position, the assembly is ready to receive a casting overlay or diaphragm. The entire second floor slab 30 is readied to receive a single cast of concrete, which will encompass the core 6 and the four wings 8. The gunwales 50 along the bottom inner chords of all module walls permit the free flow of the concrete during the cast, as described earlier. In this manner, the precast modules forming all wings 8 of the entire floor are tied together by the concrete and are also tied to the core section 6. According to the appropriate building codes, the concrete can be reinforced with structural steel rebar or with wire mesh and/or wire fabric. An accurate leveling of the poured concrete can be achieved, for example, by using a common laser reference beam as a measurement tool.

In a preferred embodiment, the cross pieces 51 used at the door openings to increase torsional strength of precast module 31 can have a height equal to the depth of poured concrete diaphragm. This ensures a smooth floor of the finished unit, and a strong anchoring of all the precast modules 31 forming a level.

To tie the core 6 and all the precast modules of wings 8 together, embedded post-tensioning steel tendons can be anchored from the exterior C and D modules at post tensioning anchor points 44, through and below the A and B modules, and into the core shear walls 60. Typical post- tensioning jack locations can be, for example, inside the elevator shaft walls (which are for example 10" thick). The steel tendons provide a horizontal tension between core section 6 and wings 8.

The post-tensioning tendons are typically stressed when the over-lay concrete diaphragm has hardened to 70% of fc'. The tendons can be encased, for example, in flexible metal ducts that are grouted after tensing to protect the tendons from corrosion. Since stress is time dependent, both the steel tendons and the concrete overlay may deform plastically under continued stress. The shrinkage of the concrete due to loss of moisture can be compensated for by the use of higher strength concrete and through the use of water-reducing admixtures (superplasticizers) and slag. The steel is of the stabilized high-strength type, to notably reduce stress relaxation.

The post-tensioning step can be an optional step. This step can thus be utilized when additional strength of the building is required, such as in seismically active areas, but can be omitted in other applications.

Step 9, variant of the over-lay procedure for floors other than the second floor.

All modules 31 are formed in the precision forms with an integral roof slab 64. This roof slab 64, typically having a thickness of between about 4" and 5", serves as the "form" on which is poured the over-lay described in step 8. In order to reduce the required strength and thus weight of the precast modules, and to eliminate the roof's deflections during the over-lay, temporary shores can be placed at key locations prior to casting of the concrete for the over-lay.

In a preferred embodiment, a finite element analysis of the structure can be performed on the modules to predict the expected deflections of all portions of the structure. Knowledge of the deflections permits an accurate placement of the temporary shoring.

Step 10. raising the tower crane.

While the second Floor slab is cast in steps 8 and 9 above, according to a preferred embodiment of the invention, separate crews can be advancing the core shear walls 28 to the fourth floor level, and can be forming a third floor slab for the core similar to the core second floor slab 27. The tower crane 20 can then be repositioned upwards by a level and bolted to the elevator shear walls between the second and third floor core slabs. In an alternate embodiment, if a sufficiently high tower sliding-sheath is used, raising the tower crane 20 can be performed only every sixth to tenth floor, thereby saving labor and time.

Step 11 , repeating the cycle of module placing, casting overlay and core advancement.

The cycle of operations described before can be repeated as many times as there are floors to be constructed. In the exemplary embodiment of a building described above, the procedure continues to the 40^th floor. The 41^st floor, if different from the residential floors, can be built conventionally. As described above, modules A, B, C and D are placed on the floor slab of the current floor so that spaces 62 are left open between vertical precast walls 33, as shown in Figure 7. When the concrete overlay for the floor of each successive level is cast, the concrete also flows in these spaces 62 of the preceding lower level. Spaces 62 thus are filled with concrete, cementing together the precast modules A, B, C, and D, and significantly increasing the strength of the structure.

The step of filling spaces 62 between vertical walls 33 of precast modules 31 , can be, in a preferred embodiment, a separate step carried out independently from the pouring of the successive floor diaphragm overlay. This step forms interior shear walls of the wings 8, that are of major structural importance, and contribute to the great strength of the completed structure. Typically, this step can be carried out before pouring the concrete diaphragm for the floor above.

The method for constructing a high rise building described according to the invention results in a number of major improvements to the structure. For example, the method produces a stiffer building capable of resisting against lateral loads due to wind and seismic activity, and exhibiting smaller lateral drift under wind loads. The building has a lowered natural frequency of vibration and higher critical damping useful in resisting earthquakes.

Other benefits of the method according to the invention are faster completion times, with, for example, a floor finished every three days versus five to ten days with conventional methods, and safer worker conditions. For example, the method eliminates the need for external scaffolding, since the external walls, windows seals, priming, painting, and most other construction and inspection tasks are performed at ground level.

Substantial cost savings are also achieved, derived from reduced material wastage, lowered insurance rates, safer working conditions, lowered accident rates, and faster completion times. A higher quality of construction can be achieved compared to conventional methods, both because workers can perform almost all of their work at ground level, and because the supervisors who check the quality and direct corrections also can work at ground level. Precision casting at ground level creates extremely accurate dimensioning and surfaces with every cast, since each cast is a mechanical copy of the other casts. Little or no adjustments need to be made to accommodate appropriate finishing.

It will be apparent to those skilled in the art that various modifications and variations can be made in the structure and the methodology of the present invention, without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims (33)

What is claimed is:

1. A method of constructing a high-rise building comprising: forming at ground level precast modules defining portions of a level of the building; lifting the precast modules in position on the level of the building; pouring a concrete overlay diaphragm on a floor of the level, such that the precast modules are held together in position; and pouring concrete in spaces between vertical walls of the precast modules.

2. The method according to claim 1 , further comprising repeating the forming, lifting and pouring steps for a selected number of levels of the building.

3. The method according to claim 2, further comprising constructing a core section of the building, said core section being connected to the level by shear walls.

4. The method according to claim 3, further comprising assembling a tower gantry crane in the core section to lift the precast modules.

5. The method according to claim 1 , further comprising the preliminary step of building a foundation and a ground level of the building, said ground level having a roof portion adapted as the floor of a second level.

6. The method according to claim 1 , further comprising forming vertical stiffening columns at selected points of the precast modules, for connection to additional vertical stiffening columns formed in corresponding additional precast modules disposed on adjacent levels of the building.

7. The method according to claim 6, further comprising threading steel dowels between the vertical stiffening columns and the additional vertical stiffening columns.

8. The method according to claim 1 , further comprising placing post- tensioning steel tendons vertically connecting outer corners of the precast modules to additional precast modules disposed on adjacent levels of the building.

9. The method according to claim 3, further comprising placing post- tensioning steel tendons horizontally connecting outermost precast modules to the core section of the building.

10. The method according to claim 1 , further comprising assembling adjacent to the building precision forms used to make the precast modules at ground level, casting concrete in the precision forms, and removing after curing the precast modules from the precision forms.

11. The method according to claim 10, further comprising, prior to casting concrete, disposing in the precision forms at least one of gunwale blocks, waffle panels, stud strips, door frames, window frames, and reinforcing elements.

12. The method according to claim 10, further comprising disposing electrical wiring and plumbing connections in the precision forms prior to casting concrete.

13. The method according to claim 10, further comprising securing at least one cross piece to the precast modules to increase torsional strength of the precast modules.

14. The method according to claim 10, further comprising finishing and inspecting the precast modules after curing the concrete.

15. The method according to claim 10, further comprising completing and testing windows of the precast modules after curing the concrete.

16. The method according to claim 3, further comprising constructing additional core levels of the core section such that each core level is substantially completed before a corresponding level of the precast modules is started.

17. The method according to claim 16, further comprising raising a self climbing tower gantry crane to the additional core levels.

18. The method according to claim 1 , further comprising building a top level of the building above the level formed of precast modules.

19. The method according to claim 1 , wherein the pouring concrete in spaces step comprises forcing concrete in the spaces left between the vertical walls when adjacent precast modules are lifted in position.

20. The method according to claim 1 , further comprising: providing passages to allow concrete to flow across vertical walls of the precast modules; and pouring the concrete overlay diaphragm such that concrete freely flows through the passages into all the precast modules.

21. The method according to claim 20, further comprising disposing a reinforcement of at least one of steel rebar, wire mesh and wire fabric adjacent the floor prior to pouring the concrete overlay diaphragm.

22. The method according to claim 20, further comprising providing interference connections between the concrete overlay diaphragm and the vertical walls of the precast modules.

23. The method according to claim 1 , further comprising setting up laser survey points to control positioning of the precast modules.

24. The method according to claim 2, further comprising shoring a ceiling portion of the precast modules before pouring the concrete overlay diaphragm in a subsequent higher level of the building.

25. The method according to claim 3, further comprising repeating the forming, lifting and pouring steps to construct a selected number of wings of the building.

26. A method of construction for a modular level of a high-rise building, the level having a floor, comprising: placing a precast module on the floor, such that the precast module defines a portion of the level of the building; placing additional precast modules on the floor to define additional portions of the level, leaving spaces between adjoining vertical walls of the precast module and of additional modules that are mutually adjacent; pouring a concrete overlay diaphragm on the floor, such that the concrete flows through passages in the vertical walls of the module and additional modules; and pouring concrete in the spaces between adjoining vertical walls.

27. The method according to claim 26, further comprising attaching post- tensioning tendons between one of the precast modules and additional precast modules and a core portion of the building.

28. The method according to claim 26, further comprising disposing metal reinforcements adjacent the floor prior to pouring the concrete overlay diaphragm.

29. The method according to claim 26, further comprising vertically connecting corners of the precast module and additional precast modules to corresponding corners of modules forming adjacent levels.

30. The method according to claim 26, further comprising forming interference fittings between the vertical walls and the concrete overlay diaphragm.

31. The method according to claim 26, further comprising defining laser survey points to accurately place the precast module and additional precast modules.

32. The method according to claim 29, further comprising forming vertical stiffening columns at selected corners of the precast module and additional precast modules, and disposing metal dowels at ends of the vertical stiffening columns.

33. The method according to claim 30, wherein forming the interference fittings comprises providing at least one of stud strips, wall waffles and floor waffles.