Masonry Magazine January 1964 Page. 9
# The Contemporary Bearing Wall
construction techniques
During 1964 a major effort of the Structural Clay Products Institute and its regional offices will be the promotion of masonry bearing wall construction. The effort is based upon extensive research by the SCPI Engineering and Technology Department, and given impetus by the contemporary desire of designers for fresh and exciting architectural forms. Masonry bearing wall construction appeals especially to those decision-makers in the building field who want to combine the beautiful and the practical. The following series of articles have been prepared by SCPI and do not necessarily represent the editorial viewpoint of this publication.
PREFACE
This series of articles is not intended to be a complete all-inclusive "manual" of wall-bearing construction techniques for the mason contractor. It is merely an introductory discussion of some of the important items we feel both the mason contractor and general contractor must consider in planning and scheduling the construction of wall-bearing buildings particularly multi-story structures if the economies inherent in such systems are to be realized. The re-emergence of clay masonry as an engineered structural building material will, no doubt, require certain changes in the general operations of the mason contractor and the general contractor alike. We hope, therefore, that the discussions that follow will stimulate the interest of both groups in seeking better and more efficient methods of building structures in which the structural properties of clay masonry are utilized to the best advantage.
PART III
INTRODUCTION
Construction management is a broad subject covering such items as financing, cost control, purchasing, scheduling, supervision, selection of equipment, safety or accident prevention and many other facets of a successful and efficient contracting operation. We are not authorities in that field, nor does space permit an extensive discussion of the whole subject of construction management. There are excellent books on the subject that would be of help to contractors wishing to learn more about it. One such book is Construction Management and Superintendence by Walter Voss.
In this section we will discuss briefly only two phases of construction management two management responsibilities that will assume even greater importance and, perhaps, some change in normal operations when the contractor is involved in the construction of a multi-story wall-bearing building. They are job scheduling and supervision.
JOB SCHEDULING
Proper materials and construction sequence scheduling of extreme importance in wall-bearing construction of more than one or two stories. A regular schedule of completion of each story, or a portion of each story, of masonry work must be maintained. The same type of schedule, with the same timing, must also control the placing and pouring of the floor systems. The entire sequence is a "leap frog" operation and a delay in one operation will delay the other. A critical construction sequence such as this requires very close coordination between the general contractor and the mason contractor.
In order to do a better job of scheduling, and to maintain a better control of costs, more and more general contractors are applying Critical Path Method (CPM) of scheduling to their operations. What is the Critical Path Method? It is a master plan of all job operations on a construction project, showing how these jobs are interrelated. It points out the longest series or path of job activities which will determine the construction schedule and completion date for a project. It answers the basic questions of when and how fast each job operation must be completed for a specific construction schedule. The Critical Path Method is based on the very obvious idea that the time required to complete the whole project depends upon the sum of the times required for only a relatively small number of essential individual jobs or activities. These essential jobs are the potential bottlenecks or trouble spots. If they fall behind schedule, the whole project is delayed and costs can go up. If they can be speeded up, the whole job is finished sooner and costs could go down. The chain or sequence of these few critical jobs within the whole job is what is called the critical path. Therefore, the critical path diagram or schedule shows clearly not only which jobs must be completed before another can be started, but also which jobs can be carried on simultaneously or parallel to others. When such a schedule is completed, management can make intelligent decisions on material deliveries, work force requirements, job supervision and the effect of possible changes which might become necessary in the construction schedule and these decisions can be made before the job is begun.
The use of CPM system involves three major steps. First, a chronological schedule of jobs or activities for the project. This schedule is graphically plotted by a line and arrow or circle diagram which shows the chronological sequence of operations.
The second step is to estimate the time normally required for each individual operation.
The third step is the calculation of schedule times. This can be done either manually or with a computer program.
Neither the time nor the space for a complete description or explanation of the critical path method is available here. There are many good references available. One which we consider excellent for the smaller contractor is A Non-Computer Approach to the Critical Path Method for the Construction Industry by Prof. John Fondahl, Associate Professor of Civil Engineering, Stanford University.
While the critical path method is mainly a tool of the general contractor, it is becoming increasingly apparent that the sub-contractor must be able to submit an accurate time schedule for the completion of his work or the whole (Continued on next page)
ASONRY.
January, 1964
9