基于FS模型的设计施工总承包联合体领导-成员风险分配策略分析

合理的风险分配是实施设计施工总承包模式的重要保障。在分析联合体成员公平偏好的基础上，通过对FS模型的改进，构建了联合体牵头方与联合体成员之间的Stackelberg博弈模型，从联合体成员嫉妒负效用以及同情正效用两方面，对联合体牵头方的最优风险分配以及联合体成员的最优风险投入进行了均衡分析。最后，采用调研获取的参数分析了不同风险承担比例下联合体成员的公平偏好系数对联合体成员风险投入、联合体成员效用、联合体牵头方效用以及联合体整体绩效的影响。特别地，联合体成员应对不同风险分配方案时会产生不同心理偏好，低分配比例情景下嫉妒偏好的增强会提高自身效用但降低联合体牵头方的效用；高分配比例情景下嫉妒偏好的增强不仅会降低联合体成员效用还会降低联合体牵头方以及整体效用，相反，同情偏好对联合体绩效具有正向调节作用。

Optimal Leader-follower Risk Allocation Strategies for Design-Build Coalitions Based on Fair Process and Social Preferences (FS) Model

Design-build is proved to be a preferred project delivery method for infrastructure projects, yet how to design an appropriate and fair risk sharing mechanism within design-build coalition (DBC) is essential to achieve project success. Further, despite the well documented literature on risk allocation for infrastructure projects, prior research has largely neglected participants' social preference which is proved to be salience in affecting their attitudes, behavior and, in turn, decision-making process. Accordingly, participants' risk management behavior will be situational, which means they will response to the risk sharing mechanism based on their perception whether the allocation ratio is fair to them. To address the gaps, a quantitative approach is presented to analyze risk sharing arrangement in design-build project by considering DBC member's fairness preference. Fehr and Schmidt's inequity aversion (IA) model is integrated into the proposed risk allocation model. The objective of this paper is to derive results for DBC leader's optimal risk-sharing ratio and DBC members' optimal risk-management effort simultaneously. The derivation is based on solving a restrained optimization problem using the conception and methods from Stackelberg game theory. Analysis results show that:(1) DBC members are prone to different fairness preference (in terms of envy preference and sympathy preference) depending on the value of risk-sharing ratio; (2) DBC members' optimal risk investment decreases with the enhancement of IA level when DBC member is envy preference; (3) DBC members' optimal risk investment increases with the enhancement of IA level when DBC members are sympathy preference; (4) It is beneficial for DBC leader to allocate more risk-sharing ratio to DBC members as their levels of envious preference increase; (5) DBC leader can allocate less risk-sharing ratio to DBC members as their levels of sympathy preference increase.Practically, the article will benefit for those who write DBC negotiation with recommendations on risk allocation strategies. Theoretically, this research sheds a light on establishing optimal risk allocation via considering members' social preference, and fills the gaps where traditional risk allocation models are based on the hypothesis of completely rational person. Accordingly, literature is enriched by providing mathematical evidence on designing a fair risk allocation strategy and, in turn, future research directions are provided for scholars to explore empirical evidence to support notions proposed in this paper.