Construction Planning and Scheduling

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Introduction

Construction activities are often exposed to various weather conditions, and often construction productivity is dependent on these weather conditions. Weather conditions are local, seasonal, and sometimes unusual. Inclement weather conditions often result in project disruptions, delays, and disputes between the project parties.

Many trades such as earthwork, concrete, roofing, and landscaping are often affected by severe weather, meanwhile other trades such as carpet installers or sheetrock installers may not be directly affected by the weather. Owners, general contractors, and subcontractors all face many risks associated with weather conditions. In order to mediate weather risks, all of the involved construction parties adopt various strategies; purchase insurance, and contract options. Typically project owners try and allocate the risks related with weather delays by adding weather clauses in the contract provisions.

The goal of this paper is to discuss the impact of weather delays in construction projects. A construction schedule should include a developed plan to allow for adverse weather. The weather considerations should be addressed during contract negotiation. By accounting for weather integration in the contract and in the baseline schedule owners and the contractor can reduce the risk of disputes from weather impacts and avoiding the rejection of claims dealing with unforeseeable or unusually severe weather. Most contracts nowadays have integrated weather calendars in the schedule.

Adverse Weather

Adverse weather, commonly referred to as severe weather, is any weather condition, rain, snow, temperature that exceeds historical data gathered over a specific period of time to establish what could be reasonably expected over the course of the construction project. Establishing unusually severe weather can be a challenging task. The most common method is to compare the actual weather experienced on the project to a historical normal for the same location. By using historical data a normal or expected level of severe weather can be established for a given time period. (Long 2010)

Normal Weather

Severe weather conditions should be incorporated in all construction contracts and in the contract it should specify the difference between normally and abnormally severe weather conditions. In contracts today, it is normal for some owners and contractors to provide the anticipated number of weather days in today’s contracts. The contracts now specify the average number of adverse weather days for certain project locations. It is in the best interest of projects to identify weather statistics, and contracts should provide the number of anticipated weather delay days based on those statistics.

Temperature

Temperature is well defined in construction contracts. The standard specifications in a contract include the minimum and maximum temperatures for many construction materials. However, temperature directly affects the productivity of workers. Most construction materials have thresholds. However, temperature is a type of weather effect in which construction does not necessarily have to be delayed when exceeding these thresholds, as long as the project can absorb expenditures for controlled measures such as heated enclosures.

Wind

Wind can affect certain construction operations, but the effect of wind on temperatures is equally important. The combination of low temperatures and wind causes wind chill, which can reduce productivity and can even be dangerous to workers. Wind alone can force several construction activities to shut down, for example high winds can make cranes unstable, which could lead to accidents. High wind also may cause fresh concrete to dehydrate on the surface. Wind not only affects the temperature and construction activities such as crane work, but wind also affects materials and material processes.

Soil Temperature

Soil temperature does not directly...
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