IES970934A2

IES970934A2 - A process for producing a steel structure

Info

Publication number: IES970934A2
Application number: IE970934A
Authority: IE
Inventors: Finian Leyden; John Curtin
Original assignee: Delciana Int Ltd
Priority date: 1997-12-23
Filing date: 1997-12-23
Publication date: 1998-02-25
Also published as: GB9800162D0; GB2332958B; IES78837B2; GB2332958A

Abstract

A process for producing a steel structure formed from a plurality of steel sub-assembly sections. Image data relating to the steel structure received and a three dimensional validation mask using is produced to identify discrete components of the structure. A validated scaled component list is then produced and parsed to automatically generate a length attribute and material characteristic for each component. Assembling each of the discrete components into the steel sub-assembly sections and dispatching adjacent sections of the structure to a site for erection to form the steel structure.<Fig.1>

Description

The present invention relates to steel structures and also to the fabrication of structural steel subassemblies used in erecting such steel structures.

For the purposes of this specification the term strut is taken to include all forms of structural steel member such as rolled steel joist, angle irons, Tee beams, I beams and channel sections etc., and the term fixing element includes base plates, gusset plates, connector plates and plates and other fixing means generally attached to structures.

Currently, steel structures are produced by connecting together a large number and wide variety of steel subassemblies. The number, size and complexity of these assemblies presents a variety of problems both in their fabrication and their subsequent assembly.

It is an object of the invention to provide a process for producing a steel structure and the required steel sub-assemblies in an efficient manner while minimising production costs and facilitating subsequent erection. It is a further objective to produce the subassemblies with a minimum of waste steel thereby optimising stock utilisation.

Statements of Invention Accordingly there is provided a process for producing a steel structure formed from a plurality of steel sub-assembly sections comprising the steps of :receiving image data relating to the steel structure, producing a three dimensional validation mask using a plurality of planar bitmap masks from the received - 2 image data and identifying discrete components of the structure; generating a scaled component list and validating the correctness of interoperation between discrete components; parsing the scaled component list to automatically generate a length attribute and material characteristic for each discrete component, storing the generated attributes and characteristics in a requirements list; interrogating a stock control database, comparing database results to the material requirements list, identifying and tagging database records suitable for use in the production of discrete components on the material requirements list and ordering in groups, material required for any shortfalls; generating a dynamic prioritised fabrication assembly schedule using the material requirements list and the three dimensional validation mask in conjunction with the database, the fabrication assembly schedule in turn generating a stock yard request list and a saw cutting list, the saw cutting list containing a preset desired sequence of operating instructions relating to the production of the discrete component parts; returning unused material to a storage area and updating the stock control database; assembling each of the discrete components into the steel sub-assembly sections and identifying each subassembly with a unique stamp; and dispatching adjacent sections of the structure to a site for erection to form the steel structure.

Preferably the step of producing a three dimensional validation mask further comprises the steps of:partitioning the received image data to identify each of the steel sub-assembly sections by dividing the data into vertical and horizontal binary planar masks, each planar mask representing a sliced section of a steel structure section; dividing each identified steel sub-assembly section in turn into discrete components by identifying adjacent vertical pixels within each planar mask having non-zero values; and producing the three dimensional validation mask by relating all of the binary planar masks taken in vertical and horizontal planes.

Ideally the number of vertical plane binary masks is equal to the maximum number of pixels in the horizontal axis of the received image data.

In one embodiment of the invention adjacent sections of the structure are grouped for dispatch in accordance with a dispatch list generated from the three dimensional validation mask.

Ideally the process includes the further step of indexing and summing sequential entries of the material requirements list according to material characteristic to produce a real-time structure estimate listing.

According to one aspect of the invention a steel structure is produced by the process.

According to another aspect of the invention there is produced a structural steel section produced by the process .

Detailed Description 5970934 - 4 The invention will be more clearly understood from the following description thereof, given by way of example only with reference to the accompanying drawing illustrating a schematic flow chart for generating a control list forming part of the invention.

Referring to the drawing there is illustrated a schematic flow chart of a process for controlling the production of steel subassemblies indicated generally by the reference numeral 100. The process 100 generates initialisation signals and a plurality of assembly signals for transmission to a variety of workstations for controlling the operation of ordering devices, stock control devices, conveyors, gripping jaws, position sensors, drills and stampers. The process 100 is also used to control machining, treating and cutting raw steel pieces to a desirable length. To ensure optimum use of materials and to guarantee the correct sequenced delivery of component steel struts. The process and its associated signals may be transmitted using any suitable transmission medium such as a computer network. Such a computer network may also allow reception of error or pause signals from the production process to pause or cease generation of further assembly signals. This significantly enhances the overall flexibility of the production process as the signals generated may be in any order and may be amended in real time.

In step 101 image data A is received. In this embodiment, the image data is a three dimensional binary mask representing an overview of the entire structure, in which each element or is defined by a plurality of pixels. The image data is organised in the conventional way, where the presence of objects is represented by a value 1 and other pixels indicating the absence of steel strut elements or fixing components have a value 0. In step 102, the received image data is partitioned using the received pixel values into individual sections, each section having a variable number of component elements. This partitioning is achieved by taking the received image data and dividing the data into a number of binary planar masks. Each of these planar masks represents a s97 09 3 4 - 5 vertical section of the building and the number of masks is equal to the maximum number of pixels in the horizontal axis of the received image data. Each section in turn is then further sub-divided into its individual components being steel struts and fixing elements, in stage 103, by identifying adjacent vertical pixels within each planar mask which have non-zero values. These adjacent values indicate a join and therefore the beginning or end of a strut or element. Further masks are taken in step 104, this time in the horizontal plane and divided in step 105 in the same manner as described above. Both vertical plane binary mask and horizontal plane mask results are combined in step 106 to produce a three dimensional validation mask B which is compared to the image data received in step 101 to ensure the accuracy of the results. In this way each strut and fixing element of the structure is identified and its position relative to adjacent struts and fixing elements is known.

In step 107 each component of the structure being strut or fixing element is identified in turn by referencing the three dimensional validation mask with a retrieved database of known elements C using a conventional pattern recognition technique to generate a component list D. A library of building validation rules E is then retrieved in step 108 and the structure validated to ensure the correctness of the structure and interoperation of the struts and elements. In this way costly design errors such as routing struts incorrectly, incorrect connections or the use of inappropriate component elements may be identified at an early stage and thus corrected before materials are ordered or fabrication begins.

The component list D has a scale factor G applied in step 110 to produce a scaled component list H. The scaled component list H is the retrieved in step 111 and parsed in according to the identified parts to automatically generate a length attribute and material characteristic for each strut and fixing element of each steel sub-assembly section in turn. These generated - 6 length attributes and material characteristics are stored in a material requirements list J in step 112 and indexed in step 113 according to material characteristic to produce a real-time structure estimate listing K in addition to indexing sequential entries of the material requirements list J are summed to produce a sum total for each of the materials required to produce the struts and fixing elements in the estimate listing K. The use of this technique in addition to eliminating design errors further allows sales personnel to establish the costing implications of any design modifications or customer change requirements in real time as the steel ordering requirements will change accordingly.

When the correctness of the design has been confirmed the estimate listing K is routed to an order processor in step 114. The order processor retrieves a database of standard component lengths M and a stock control database N in step 115. Each material type required for the construction of the structure is read from the estimate listing K together with the sum total requirement in turn and compared with the database N. Where items of stock are found this are tagged in the stock control database N as assigned to a structure in step 116. Material requirements not found in stock are referenced to the database of standard component lengths M and compiled in a material order list P in step 117 which is used to generate necessary the necessary purchase orders.

It is an important feature of the current invention that materials from different subassemblies are ordered together and that they are grouped so as to match standard lengths from suppliers. Thus for example wherever possible rolled steel joists are ordered in lengths available from producers stock to reduce lead time and in lengths which may be easily transported on standard haulage equipment to reduce carriage costs.

The assigned records of the stock control database N are retrieved in step 122 and referenced to the scaled component list H to determine which sections it is 5970934 - 7 possible to fabricate from existing stock. When it is determined that it is possible to fabricate a section from existing stock an entry is made on an assembly schedule Q in step 123. If it is determined that it is possible to make more that one sub-assembly section the assembly schedule Q is automatically prioritised in accordance with the component list H to ensure that sections required first for assembly of the entire structure are fabricated first. Care is given in this prioritisation to take account of section construction times and delivery schedules.

It will be appreciated that in this way construction of the various section in the structure is optimised to ensure maximum productivity and minimum lead times. As new stock is delivered in response to the material order list P and the purchase orders, entries are made to the stock control database N. Each purchase order is assigned an eight bit binary code word so that as the stock arrives it is automatically assigned in accordance scaled component list H and routed to cutting (see below), immediate fabrication or stock to await delivery of further items. In this way work scheduling is fully automated requiring a minimum of intervention by operatives. A certain quantity of stock is maintained in the stock yard as not all of the standard lengths ordered by the material order list P will be used in a single structure and these are returned to stock with the assigned flag unset indicating availability. This allows for optimal stock control and minimises capital operating cost requirements. It will be noted that a priority sequence controller attempts to assign items to the scaled component list H from return to stock pieces before attempting to effect alternate assignment techniques .

The assembly schedule Q contains a section identifier and a complete part listing for each section. Construction of a given section begins in step 124 with the generation of a stock yard request list R from the assembly schedule Q. The request list R is transmitted to the stock yard in step 125 and contains a location 5970934 - 8 data word to indicate the physical position of the stock item in addition to data relating to the material type and length. This information is used to retrieve the stock item and deliver it to a saw in step 126. The assembly schedule Q is then accessed in step 127 to generate a saw cutting list S for the stock item delivered in step 128. The saw cutting list S is transmitted to the saw in step 127 and contains an initialisation control signal to move the stock item onto a conveyor system and to an initialisation position. The list S also contains move, clamp and cut instructions to move the stock item, for example a rolled steel joist, a given distance from the initialisation position, clamping the joist and cutting at that position. In this way accurate cuts are ensured eliminating losses due to incorrect measurements etc. Where the entire stock item is required for immediate fabrication appropriate cuts are made and the item delivered to downstream fabrication stations in accordance with a continuation signal from the assembly schedule Q in step 129. However, if only a portion of the delivered item is required a return to stock signal from the assembly schedule Q is produced in step 130 the destination location being recorded in the stock control database N for future use. In addition to the saw instructions drill instructions, shot blast instructions and paint instructions are similarly routed to appropriate stations to control prefabrication of the section under construction. The data configurations of these instructions vary in accordance with the machine being controlled and are normally transmitted across a fibre optic link to overcome inherent operating electrical noise.

In addition to these instructions a stamp instruction is transmitted across a fibre-optic link to a stamping station from the assembly schedule Q in step 131. This stamp instruction is generated to produce the erection mark 3. This erection mark is positioned on the upper right hand corner of each section to facilitate erection of the structure. The position of the mark on each section is determined by defining a common reference <59 7 Ο 9 - 9 point and applying it to the three dimensional validation mask B. When the sections have been fully assembled and stamped they are delivered to a dispatch area and grouped in accordance with a dispatch list generated in step 132 from the three dimensional validation mask B. This ensures that adjacent sections are delivered together in accordance with the delivery capacity of the transport vehicles to prevent undue storage on site of delivered sections and therefore possible accidental damage. It further prevents undue construction delays already greatly minimised by the provision of a unique erection mark 3 on each section and allows construction to begin wherever possible while fabrication work is in progress and frequently while awaiting delivery of struts or fixing means.

The invention is not limited to the embodiment hereinbefore described, which may be varied in both construction and detail.

Claims

1. A process for producing a steel structure formed from a plurality of steel sub-assembly sections comprising the steps of:receiving image data relating to the steel structure, producing a three dimensional validation mask using a plurality of planar bitmap masks from the received image data and identifying discrete components of the structure; generating a scaled component list and validating the correctness of interoperation between discrete components; parsing the scaled component list to automatically generate a length attribute and material characteristic for each discrete component, storing the generated attributes and characteristics in a requirements list; interrogating a stock control database, comparing database results to the material requirements list, identifying and tagging database records suitable for use in the production of discrete components on the material requirements list and ordering in groups, material required for any shortfalls; generatinq a dynamic prioritised fabrication assembly schedule using the material requirements list and the three dimensional validation mask in conjunction with the database, the fabrication assembly schedule in turn generating a stock yard request list and a saw cutting list, the saw cutting list containing a pre-set desired sequence of operating instructions 5870»W - 11 relating to the production of the discrete component parts; returning unused material to a storage area and updating the stock control database; assembling each of the discrete components into the steel sub-assembly sections and identifying each sub-assembly with a unique stamp; and dispatching adjacent sections of the structure to a site for erection to form the steel structure. A process as claimed in any claim 1 wherein the step of producing a three dimensional validation mask further comprises the steps of:partitioning the received image data to identify each of the steel sub-assembly sections by dividing the data into vertical and horizontal binary planar masks, each planar mask representing a sliced section of a steel structure section; dividing each identified steel sub-assembly section in turn into discrete components by identifying adjacent vertical pixels within each planar mask having non-zero values; producing the three dimensional validation mask by relating all of the binary planar masks taken in vertical and horizontal planes; and indexing and summing sequential entries of the material requirements list according to material characteristic to produce a realtime structure estimate listing. S»7 Ο» 3 4 - 12 A process as claimed in claim 2 wherein the number of vertical plane binary masks is equal to the maximum number of pixels in the horizontal axis of the received image data. A process as claimed in any preceding claim wherein adjacent sections of the structure are grouped for dispatch in accordance with a dispatch list generated from the three dimensional validation mask. 10 5 A process for producing a steel structure substantially as hereinbefore described with reference to the accompanying drawings.