Rate Calculation Sheet

A rate calculation sheet is used to compile the internal makeup of a pricing sheet. In its most basic form, it will simply comprise a list of resource components that are required to complete an activity on site. If the resource components all had the same unit of measurement as the pricing sheet, then their allowables could simply be summed to provide a total allowable for the pricing sheet. In reality, however, this scenario is rare. It is common for the unit of the resources in a rate calculation sheet to differ with respect to one another and also with respect to the unit of measure of the bill item being priced.

An example of a bill item to "Plaster Interior Walls 25mm" thick will now be considered. Plastering is measured per square meter (m2), which is also the unit of the worksheet.

To perform plastering requires three resource components namely:

• Plasterer (one), General Labor (three), and Mortar.

We assume that the resources have been properly defined earlier. Mortar is actually a Resource Cluster, i.e. it comprises cement + sand + water and its allowable rate is built up taking that into account. For the purposes of this example, Mortar can be treated like any other resource. Resource Clusters are described in Resource Clusters. The resource components are now added to the worksheet in the following steps and as shown in Figure: Insert Resources into Worksheet.

1. Open the bill item "Plaster Interior Walls 1in" in the BOQ Item Editor and select its worksheet (Plaster Interior Walls). Open the INSERT tab (1. Insert)

2. Search for resource "Plasterer" (2. Search Plasterer)

3. In the list, (3. Select and insert) the Plasterer. Notice that (4. Plasterer is added as a resource component).

4. Repeat the above steps for General Labor.

5. (5. Open tab Insert Clusters), then repeat steps 1 - 3 to insert Mortar Cluster

In summary, the Insert action tab presents users with a full, searchable list of all of the Resources present in the project. Resources can be inserted into the Calculation Sheet by selecting the checkboxes next to the appropriate Resources and pressing the “Insert Selected” button below the table. Options are also available to create and insert new Resources or to duplicate and insert existing Resources via the “Create & Insert Resource” and “Duplicate & Insert Selected” buttons respectively. The option to duplicate and insert existing resources is used when the user intends to change the existing resources. The changes will then only apply to the duplicated resources and not to the parents from which they were cloned.

Resources can also be inserted from an external data source, by selecting the data source in the data source field at the top of the Insert tab.

The allowable cost and unit of each resource are part of their definition. These are brought forward to the allowable and unit columns of the price calculation sheet as shown in the figure:

• Plasterer, $30.00 per hour,

• General Labor, $200.00 per day (shift) and

• Mortar, $215.26 per cubic yard (yd3).

Notice also that the default TRANSFORM "*1" is listed for each resource. This must now receive attention.

Since the allowable rate to "Plaster Interior Walls 1in" has to be computed per square foot (ft2), the mismatching units of the resource components have to be accounted for in the computation. For this, the production/consumption rates of the resources must be known:

• In a standard 8-hour day, a Plasterer completes 270 square feet of plastering.

• The plasterer is supported by a team of 3 General Laborers that implicitly also completes 270 ft2 of plastering per day.

• For 1-inch thick plastering, 0.003yd3/ft² plus 15% wastage of Mortar is consumed.

Given these values, the allowable for one square meter of 1in plaster can be computed as shown in the table below.

As can be seen in the table above, transform factors have to be applied to adjust the allowable and unit of resource component to match that of the worksheet. Only once these transformations have been applied, can the allowable of the worksheet be correctly calculated. The purpose of the rate calculation sheet is to provide an environment in which the user can assign appropriate transform factors to individual resource components and systematically build up the allowable rate of the associated bill item. To update a transform factor, double-click on the appropriate cell to engage editing mode and specify a new transform calculation, as shown in Figure: Rate Calculation Sheet.

The transform calculations in Trimble Quest must adhere to the following syntax:

• All transform factors must start with a multiplication (*) or division operator (/)

• All basic mathematical operators are supported within a transform calculation: addition (+), subtraction (-), multiplication (*), division (/), and power (^). Some basic trigonometry functions are also supported: sine (sin), cosine (cos), and tangent (tan). All trigonometric functions expect angles in radians.

• Parenthesis is supported via round brackets ( ).

• All addition and subtraction calculations within a transform must be encapsulated within parenthesis.

• The order of operations is in line with that of standard mathematics (Brackets, Power, Division, Multiplication, Addition, Subtraction).

• IF-statements with the syntax IF(test ; when true ; when false) are supported.

• Variables are supported and must be within curly brackets { }. Variables are described in Variables

• Everything within square brackets [ ] within a transform is ignored by the equation compiler, i.e. it is treated as comments. It is typical to add unit conversions within these square brackets to express intent and improve the readability of a transform. This helps especially when a new/different user views a worksheet to understand what the originator was thinking when the worksheet was created.

• Examples of valid transforms: *8[hrs/day]*(2 + 2), *2[no]/1000[m3/day], *12[ltr/hr]*8[hrs/day], *8*2^2, /100[m/day], *IF({x}>{y};{x};0)

Note: Even though Trimble Quest will check the validity of the syntax of the transforms, it will not enforce or check that the Unit transformations are correct or meaningful. Since Units carry no semantic meaning within the system, it will be up to the user to ensure that the transformations are correct.

The priced bill item "Plaster Interior Walls 1in" with Allowable breakdown is shown in Figure: Priced Bill Item with Allowable breakdown.

Next topic: Variables