[雙語(yǔ)翻譯]外文翻譯--可持續(xù)發(fā)展混凝土基于規(guī)格性能的作用

1、中文 中文 7300 字， 字，4400 英文單詞， 英文單詞，25500 英文字符 英文字符文獻(xiàn)出處： 文獻(xiàn)出處：Lemay L, Lobo C, Obla K. Sustainable Concrete: The Role of Performance-based Specifications[C]// Structures Congress. 2013:2693-2704.原文 原文Sustainable Concrete: T

2、he Role of Performance-based SpecificationsLionel Lemay1, Colin Lobo2 and Karthik Obla31 National Ready Mixed Concrete Association, 1244 Crane Blvd., Libertyville, IL, 60048; PH (847) 918-7101; email: LLemay@nrmca.org2 N

3、ational Ready Mixed Concrete Association, 900 Spring Street, Silver Spring, MD, 20910; PH (240) 485-1160; email: CLobo@nrmca.org3 National Ready Mixed Concrete Association, 900 Spring Street, Silver Spring, MD, 20910; PH

4、 (240) 485-1163; email: KObla@nrmca.orgABSTRACTConcrete is used in nearly every structure we build today, including buildings, bridges, homes and infrastructure. With greater emphasis placed on sustainability in recent y

5、ears, structural engineers are faced with the challenge of meeting traditional design criteria in addition to evolving criteria that support sustainable construction. Performance-based specifications for concrete can sub

6、stantially help meet this new challenge. Prescriptive requirements such as minimum cement content or maximum water to cement ratio are among many common specification requirements that can increase the environmental foo

7、tprint of concrete. This paper outlines how concrete performance can be improved while lowering environmental footprint by implementing performance-based specifications.INTRODUCTION Sustainable concrete is difficult to d

8、efine. There are many factors that can influence the way concrete is manufactured, designed, built, used and recycled that ultimately affect the environmental footprint of concrete and the structures built with concrete

9、. Whether one is designing a high rise building, pavement, bridge, dam or warehouse, concrete is an important component used as foundation and superstructure, and these structures can have a significant impact on our e

10、nvironment throughout their lifecycle. Structural engineers can influence the performance and environmental impact of structures through effective design and specifications regardless of the materials being used. Howeve

11、r, concrete is unique in that it so versatile both in terms of physical characteristics (size, shape, appearance, etc.) and mechanical properties (strength, stiffness, permeability, etc.) that structural engineers can

12、influence performance, including environmental impacts, of concrete and concrete structures significantly through design decisions and project specifications.INFLUENCE OF DESIGN DECISIONSThe single biggest influence an

13、engineer can have on the environmental impacts of a structure is through efficient design. The following are several factors that affect the performance of concrete and concrete structures:Design Loads. Every structure

14、, at a minimum, must be designed to resist forces from gravity, service, wind, earthquakes, water, soil, fire and blast, among others. If a of these consequences of prescriptive specification requirements could render t

15、he project unsustainable. Energy Efficiency. Concrete buildings are typically more energy efficient than lighter framed buildings because of thermal mass. Thermal mass is a material’s ability to store heat and release i

16、t over time. There are three characteristics of thermal mass. First, the time lag between peak heating and cooling loads and outside temperature peaks is greater for massive buildings. This feature can be used in buildin

17、gs by delaying the need for heating or cooling energy to take advantage of off- peak demand. In an office building, that means you can delay heat gain until after everyone has gone home. Second, massive buildings have

18、lower peak heating and cooling loads allowing for smaller more efficient heating and cooling equipment. And third, massive buildings require less overall heating and cooling energy to maintain the same interior tempera

19、tures since temperature swings are moderated.In a research report published by the Massachusetts Institute of Technology (MIT), the effects of thermal mass were explored using life cycle analysis for a 12-story, 46,321 m

20、2 (498,590 ft2) commercial building. The building was analyzed for a 60- year life for two climates, Phoenix and Chicago, and for two different structural materials, concrete and steel. The analysis demonstrated that th

21、e greenhouse gas emissions due to operational energy of the building are responsible for 95-96% of life cycle emissions. Figure 1 demonstrates that the concrete building has approximately the same embodied emissions as

22、steel, but has lower operating emissions, which can lead to lower life cycle emissions (Ochsendorf 2011).Figure 1. Total Global Warming Potential (GWP) over 60-year lifespan for commercial buildings.Research at Lawrence