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אומדן ותמחור

הפקת elemental cost plan לפי Australian Cost Management Manual

קבעו את ה-gross floor area ואת יחידת התפקוד, בנו את התוכנית אלמנט אחר אלמנט לפי רשימת האלמנטים של AIQS, תמחרו כל אלמנט מפרויקטים שנותחו, עדכנו לאמצע הבנייה, שמרו את ה-contingencies של תכנון ובנייה נפרדות, והפיקו תוכנית שאפשר להשוות אליה את הבאה.

6 שלבים18 דק׳ייעוץ עלויות / כמויותיזם / לקוחמשרד ניהול פרויקטים / בנייה

איך זה עובד, שלב אחר שלב

6 שלבים לאורך הפלטפורמה - מה עושים בכל שלב ולמה זה חשוב.

1

Fix the area, the functional unit and the exclusions

בסיס האומדן

Record the gross floor area the plan is built on, measured the way the manual measures it, the functional unit the client thinks in, beds, car spaces, classrooms or seats, and the list of what the plan excludes: land, authority charges, loose furniture, client contingency and the escalation beyond the horizon you have priced to.

למה: Two cost plans for the same building differ by a fifth when they measure area differently, and neither is wrong. Everything downstream is a rate per square metre, so an area defined loosely puts the same looseness on every element at once, and no later check finds it because every element is internally consistent.

נכנסProject brief and area scheduleDesign stage reachedיוצאGross floor area agreedInclusions and exclusions stated
2

Build the plan element by element

אומדן ראשוני

Work down the element list rather than around the drawing: substructure, columns, upper floors, staircases, roof, external walls, windows and external doors, internal walls and doors, the three finishes, fittings, services and external works. Each element carries its own quantity, its element unit quantity and its cost, so the number can be argued about one element at a time.

למה: An element list worked through in order is also a completeness check, because an element with nothing against it is visible and a missing trade in a lump sum is not. It is how a plan produced in a day still has a roof in it.

נכנסGross floor area agreedConcept drawingsיוצאCost plan by elementElement quantities
3

Rate each element against projects already analysed

סייר עלויות

Compare each element unit rate with the same element on completed projects of the same type, and write down the reason for every element that sits outside the range. A facade rate double the library is either a design decision worth naming or an error, and the difference between those two is a sentence.

למה: Elemental analysis exists so that a plan can be challenged before it is approved rather than after it is exceeded. An element that nobody could explain at the design review is the same element that becomes the overrun, and it was visible months earlier.

נכנסCost plan by elementAnalysed projectsיוצאElements benchmarkedOutlying elements explained
4

Escalate to the middle of construction, not to today

מדד מחירים

Record the base date the rates are current at, then escalate them to the midpoint of the construction period the programme implies. State both dates on the plan, and state the index you escalated with.

למה: A cost plan priced at today's rates for a building that starts in eighteen months is wrong on the day it is issued, and it is wrong in the direction nobody wants to discover later. Naming the base date is what lets a board read the number as an estimate of a future cost rather than as a price.

נכנסElements benchmarkedIndicative programmeיוצאEscalated to a stated dateBase date on the record
5

Keep the two contingencies apart

הקצבות ורזרבה

Carry a design contingency for the drawings that are not finished yet and a separate construction contingency for what the site will find, each as its own entry with what it is for. Reduce the design one as the design is resolved rather than letting it drift into the construction one.

למה: One combined contingency answers no question. It cannot be released as the design firms up, because nobody can say which part was for the design, and it cannot be defended when the site finds rock, because it has already been spent on documentation gaps.

נכנסEscalated to a stated dateKnown design gapsיוצאDesign contingencyConstruction contingency
6

Issue it against the plan it replaces

דוחות

Issue the plan with the element table, the rate per square metre, the rate per functional unit and a reconciliation against the previous plan that says which elements moved and why. Keep it as the version the next design review is measured from.

למה: A cost plan issued without a reconciliation is a new number rather than a report on the old one, and the conversation it produces is about whether to believe it. With the movement written out element by element, the same meeting is about four decisions that were already made.

נכנסComplete cost planPrevious cost planיוצאCost plan issuedMovement since the last plan
מודולים

המודולים בתרחיש הזה

6 מתוך 190 מודולי הפלטפורמה

The market this case is written for

אוסטרליה

Everything in this case follows how construction work is measured, priced and paid for in this market. The forms, the cost breakdown and the payment rules are the ones used there, not a generic version of them.

Standards it follows

  • AS 4000
  • Security of Payment Act

You do not have to set any of that up by hand. The first time you open the platform it asks which market you work in. Choose this one and it sets the interface language, loads the matching cost database and records the cost classification, and it adds an example project you can open straight away.

The rule checks for this market come with the platform too. Switch them on once and an estimate that misses something the market expects is flagged while you are still working on it, not after the tender has gone out.

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