1、Lesson 27 Formwork 模板Words consistent with意為意為“與致與致”setting of the cement意為意為“水泥的凝固水泥的凝固”form tie意為意為“模板拉桿模板拉桿”architectural concrete意為意為“裝飾用混裝飾用混凝土凝土”handling equipment意為意為“吊運設(shè)備，吊運設(shè)備，裝卸設(shè)備裝卸設(shè)備”fiberglass plastic form意為意為“玻纖增強玻纖增強塑料模板塑料模板” permanent a.永久的、持久的永久的、持久的Underdesign n.安全系數(shù)不足的設(shè)計安全系數(shù)不足的設(shè)計Ove

2、rdesign n.安全系數(shù)過大的設(shè)計，安全系數(shù)過大的設(shè)計，solid substance 固態(tài)物質(zhì)固態(tài)物質(zhì)Attain v.達到，獲得達到，獲得Semiliquid n.半流體半流體Plastic a.塑性的，可塑的塑性的，可塑的Exert v.施加（壓力等施加（壓力等）Cement n.水泥，膠凝材料水泥，膠凝材料Deposit v.堆積，有效，沉淀；堆積，有效，沉淀；nLumber n.木材木材Plywood n.膠合板，層壓木板膠合板，層壓木板Screw n.螺打螺打Accessory a.附屬的，補充的附屬的，補充的plywood form 膠合模板膠合模板steel form 鋼模

3、板鋼模板Disassemble v.拆卸，分解拆卸，分解Precaution n.頓防，警悔，防范頓防，警悔，防范Insulation n.隔熱，保溫隔熱，保溫aluminum form 鋁鋁模板模板plastic form 塑料模板塑料模板Fiberglass n.玻璃纖維玻璃纖維Lightweight a.輕質(zhì)的輕質(zhì)的internal friction 內(nèi)摩擦內(nèi)摩擦Magnitude n.大小，數(shù)量大小，數(shù)量Design of FormsForms for concrete structures must resist the pressures to which they are sub

4、jected and support the loads imposed on them. In order to assure adequate strength and rigidity consistent with maximum economy，forms must be designed with the same care and engineering principles that are used to design the permanent members of the concrete structures. Underdesigning can result in

5、the failure of the forms, and overdesigning will result in excessive costs.Formwork is the term given to either temporary or permanent molds into which concrete or similar materials are poured.Design of FormsIn order to design forms properly it is necessary to have certain basic information. This in

6、cludes a knowledge of the pressure produced by，or the weight of the concrete on，the forms，including both static and dynamic forces，as well as a knowledge of the physical properties of the materials used for the forms.When concrete is first mixed，it has properties lying between those of a liquid and

7、those of a solid substance. It is best described as a semiliquid，and is usually defined as a plastic material. With the passage of time, concrete loses its plasticity and changes into a solid. This property of changing from a plastic to a solid makes concrete a valuable building material because it

8、can be easily shaped by forms before attaining its final state.Materials used for formsMaterials used for forms for concrete structures include lumber, plywood, hardboard, plastics, steel, and aluminum. Additional materials include nails, bolts, screws, form ties, and other accessories.Among the pro

9、perties that form materials should possess are the following ：Adequate strengthAdequate rigiditySurface smoothness, where requiredEconomy，considering initial cost and number of reusesplywoodhardboardlumberplasticssteelaluminumPlywood formwork and Steel formworkPlywood is used extensively for formwor

10、k for concrete. Among the advantages are smooth surfaces，availability in a variety of thicknesses and lengths，and ease of handling during construction.Steel Forms Steel forms are of two broad types： those that are prefabricated into standard panel sizes and shapes and those that are fabricated for s

11、pecial uses. For some projects either one or both types may be used. Among their uses are the following ：Concrete wallsConcrete piers, columns, and related itemsConcrete tunnel linings and concrete damsPrecasting concrete membersArchitectural concreteSteel formwork For certain uses，forms made of ste

12、el have several advantages over forms made of other materials. They can provide adequate rigidity and strength. They can be erected， disassembled, moved, and re-erected rapidly, provided suitable handling equipment is available for the large sections. They are economical if there are enough reuses.

13、The smooth concrete surface may be an advantage for some projects. Forms made of steel have some disadvantages. Unless they are reused many times， they are expensive. Also, unless special precautions are taken，they offer little or no insulation protection to concrete placed during cold weather.Alumi

14、num FormsForms made from aluminum are in many respects similar to those made of steel However, because of their lower density, aluminum forms are lighter than steel forms，and this is their primary advantage when compared with steel. Because the strength of aluminum in handling，tension，and compressio

15、n is less than the strength of steel, it is necessary to use larger sections when forms are made of aluminum. Since wet concrete can chemically attach aluminum, it is desirable to use aluminum alloys in resisting corrosion from the concrete.Plastic Forms & Fiberglass Plastic Forms Plastic Forms, fib

16、erglass plastic forms can be used for unique shapes and patterns in concrete. In addition to their ability to form unusual shapes，plastic forms are lightweight, easy to handle and strip, and they eliminate rust and corrosion problems.Practice: translate the following text into Chinese Forms for concrete structures must resist the pressures to which they are subjected and sup